Remove JpaUtils and refactor repository access

Eliminated the static `JpaUtils` utility and transitioned to explicit repository management for improved modularity and testability. Updated `GuildService`, `TaskManagerImpl`, and related classes to use dependency-injected repositories. Simplified configuration by aligning repository definitions with existing service patterns and ensuring proper session handling through `SessionManager`. Verified that all affected components function as expected after refactoring.

.junie/plans/db-package-best-practices.md

@@ -0,0 +1,309 @@
+---
+sessionId: session-260925-080906-1d5c
+---
+
+# Findings
+
+### Correctness bugs (highest priority)
+| # | Where | Problem |
+|---|---|---|
+| B1 | `BlacklistRepository.delete/add` | `getWordFromDb` loads the entity in its **own session** (which it also closes twice). The caller then calls `session.remove(bl)` in another session on that **detached** entity, which Hibernate rejects with `IllegalArgumentException`. The exception is swallowed by `BlacklistService`, which returns `warn`. |
+| B2 | `GuildSettingRepository.setSettingValue` | Runs inside `JpaUtils.getWithSession`, which has **no transaction**, so `merge`/`remove` are never flushed or committed. Updating or resetting a setting is probably lost; only an IDENTITY `persist` happens to insert. |
+| B3 | `Repository<O>` | IDs are always `String`, but `OBlacklist.id` / `OGuildSetting.id` are `Integer`, so `deleteBy`/`findById` bind a type-mismatched parameter. `BlacklistRepository.findById` returns `null` outright. |
+| B4 | `Repository.save`, `JpaUtils.updateWithTransaction` | Every non-constraint exception is swallowed after `logger.error(e)`, so callers think the write succeeded. `runWithTransaction` never rolls back on failure. |
+| B5 | `JpaUtils.tryLoad` | Uses the deprecated `Session.load(Object, id)`. It closes a session it doesn't own and calls back into `GuildService` (a hidden circular dependency). |
+| B6 | `MessageRepository.getMessageString` | NPE when the message isn't found. |
+| B7 | `SessionManager.getSessionFactory` | Lazy initialization isn't thread-safe. The Hibernate factory is built **before** Flyway migrates, and the schema is never validated. |
+
+### Design / best-practice issues
+- **Static service locator.** `JpaUtils.bind` / `bindGuildServiceLookup` (called from `App.java` l.119, l.138) hide dependencies and make repositories untestable.
+- **Duplicated CRUD.** Five repositories copy-paste `findAll` / `findById` / `deleteBy`. They use the "lambda + external `ArrayList`" workaround because the helpers can't return values.
+- **Duplicated JDBC config.** `SessionManager` and `DatabaseMigration` both build the URL, user and password from settings.
+- **Layering.** Repositories take JDA types (`Member`, `Message`, `MessageChannel`), and `MessageRepository.log` carries a `//TODO: move to a service`.
+- **Services create their own repositories** with `new`. `TaskService.persistTask`/`unpersistTask` even shadow the repository field it already holds.
+- **Caches.** `GuildSettingService.reloadSettingsCache` clears the map and then refills it, so readers can see it empty. `getSettings()` and `GuildServiceProviderImpl.getServices()` leak mutable maps. Guild services are never evicted.
+- **Logging mix.** The package uses both Log4j `LogManager` and SLF4J.
+- **Entities.** No `equals`/`hashCode`. The field is named `OLoggings`. `OWebUser` is missing from `hibernate.cfg.xml`.
+- **Hygiene.** Duplicated copyright headers and a broken `package ...;/*` line in `GuildRepository` and `GuildSettingRepository`. `GSettings` has a `//TODO: description`.
+- **No tests** for the `db` package.
+
+# Requirements
+
+### Overview & Goals
+Make the persistence layer (`me.bobert.netneutrality.db` and subpackages) correct, testable and idiomatic for Hibernate 7.1 / Java 25. Services become pure domain code with no JDA or command types. User-visible bot behavior stays the same except for the bug fixes (writes actually persist, errors surface).
+
+> Chosen options: **Full redesign**, **injected generic base repository**, **Testcontainers MySQL** tests.
+
+### Scope
+**In scope**
+- Fixes for bugs B1–B7 (see Findings).
+- Replace the static `JpaUtils` with constructor-injected `SessionProvider` and a generic `AbstractRepository<T, ID>`.
+- A single `DatabaseConfig` shared by Hibernate and Flyway. Migrate first, then build the factory with `hbm2ddl.auto=validate`.
+- Service cleanup: inject repositories, safe cache swaps, no JDA types in repositories.
+- **Decouple services from JDA and `CommandExecutionResult`.** Services take plain IDs and return domain results. The callers (`BlacklistCommand`, `ConfigureCommand`, `MusicCommand`, `MusicManager`, `EventsHandler`, `ActionRoutes`, `BotState`, `TaskManagerImpl`, `LoadPlaylistTask`) map those results to replies.
+- **Rework the guild-service cache.** `GuildServiceProvider` keys by guild ID only, evicts on `GuildLeaveEvent`, and exposes read-only snapshots.
+- Entity hygiene and consistent logging (Log4j API, matching `App` and `SessionManager`).
+- Testcontainers-based integration tests.
+
+**Out of scope**
+- Switching to Spring or JPA `EntityManager`, or changing the Flyway schema (a migration is added only if validation shows an actual mismatch).
+- Changing command UX: slash command names and options, and the reply wording (messages stay equivalent).
+- Changes to `CommandExecutionResult` itself or to the command framework (`core.command`).
+
+### Functional Requirements
+- Adding or removing a blacklist word persists, and the cache reflects it right away.
+- Setting a guild setting to a non-default value inserts or updates it. Setting it to the default or `null` deletes the row. All of this happens in one transaction.
+- Persistence failures propagate as exceptions and are rolled back. They are never silently logged.
+- When the bot starts: Flyway migrates first, then Hibernate validates the schema. If either fails, startup aborts with a clear error (Sentry is kept for non-dev environments). The password is never logged.
+- A missing `OGuild` gets recreated through `GuildService.findOrCreateGuild` instead of the `tryLoad` side channel.
+- No class in `db.service` or `db.repository` imports `net.dv8tion.jda.*` or `me.bobert.netneutrality.core.command.*`.
+- The blacklist add/remove replies stay equivalent: success, "already exists" and "not found" become distinct outcomes, and unexpected errors are shown as a warning by the command.
+- When the bot leaves a guild, its row is deleted and its cached `GuildService` is evicted.
+
+# Technical Design
+
+### Key Decisions
+1. **Constructor injection instead of a static locator.** Repositories receive the `SessionProvider` (not the `SessionFactory`), because the factory is only built in `start()`. `JpaUtils` is deleted.
+2. **Use Hibernate 7's native helpers** `SessionFactory.fromTransaction` / `inTransaction` / `fromSession`. They handle begin, commit, rollback and close correctly, so no hand-written transaction code is needed.
+3. **Generic ID type.** `AbstractRepository<T, ID>` takes the entity class and uses `session.find`, `merge` and `remove` on a managed instance.
+4. **Queries and writes run in the same session.** This fixes B1 and B2 by construction.
+5. **Migrate, then validate.** Flyway runs before the factory is built, and `hibernate.hbm2ddl.auto=validate` catches drift between entities and schema.
+6. **Services return domain outcomes; commands turn them into replies.** Services return small enums/records such as `BlacklistResult { ADDED, REENABLED, ALREADY_EXISTS, REMOVED, NOT_FOUND }` and never `CommandExecutionResult`. They take `String` IDs, not `Member`/`Guild`/`Message`. Unexpected persistence errors propagate, and the command layer catches them and shows a warning.
+7. **ID-only provider API.** `GuildServiceProvider.get(Guild)` is removed (callers pass `guild.getId()`). The provider adds `evict(String)`, and `getServices()` becomes `snapshot()`, which returns `Map.copyOf`.
+
+### Data Models / Contracts
+```java
+public record DatabaseConfig(String url, String user, String password) {
+    static DatabaseConfig from(SettingsProvider s) { ... } // MYSQL_* keys, same defaults
+}
+
+public abstract class AbstractRepository<T, ID> {
+    protected final SessionProvider sessions;
+    private final Class<T> type;
+    protected AbstractRepository(SessionProvider sessions, Class<T> type)
+    public List<T> findAll()                 // fromSession + criteria/HQL
+    public Optional<T> findById(ID id)       // session.find
+    public T save(T entity)                  // fromTransaction(s -> s.merge(entity))
+    public void deleteById(ID id)            // inTransaction: find + remove
+    protected <R> R read(Function<Session, R> work)   // sf.fromSession
+    protected <R> R write(Function<Session, R> work)  // sf.fromTransaction
+    protected void writeVoid(Consumer<Session> work)  // sf.inTransaction
+}
+```
+Repositories and their key queries:
+- `GuildRepository extends AbstractRepository<OGuild, String>`.
+- `BlacklistRepository<OBlacklist, Integer>`:
+  - `findByGuildId`
+  - `findEnabledWords(guildId)` returns `Set<String>`
+  - `enableWord(OGuild, creatorId, word)`
+  - `deleteWord(guildId, word)`
+- `GuildSettingRepository<OGuildSetting, Integer>`:
+  - `findByGuild`
+  - `upsertOrDelete(guildId, name, value, default)`, which queries the setting directly instead of using the lazy collection.
+- `TaskRepository<OTask, String>`.
+- `MessageRepository<OLogMessage, String>`:
+  - `findByMessageId`
+  - `updateEditedMessage`
+  - `findByUser(... ORDER BY dateSent DESC)`
+  - `log(...)` takes plain values (IDs, content, `Instant`) instead of JDA types.
+
+Service contracts after the redesign:
+```java
+public enum BlacklistResult { ADDED, REENABLED, ALREADY_EXISTS, REMOVED, NOT_FOUND }
+
+public class BlacklistService {
+    BlacklistResult add(String creatorUserId, String word);
+    BlacklistResult remove(String word);
+    List<BlacklistEntry> list();              // record BlacklistEntry(String word, boolean enabled)
+    boolean containsBlacklistedWord(String text);
+}
+
+public class GuildSettingService {
+    void set(GSettings key, @Nullable String value); // null/default => delete
+    Optional<String> get(GSettings key);
+    Map<String, String> snapshot();                  // unmodifiable
+}
+
+public interface GuildServiceProvider {
+    GuildService get(String guildId);
+    void evict(String guildId);
+    Map<String, GuildService> snapshot();
+}
+```
+
+### Proposed Changes
+- **`SessionManager`**
+  - Hold a `DatabaseConfig`.
+  - `start()` runs `DatabaseMigration.migrate(config)` and then builds the factory eagerly (`synchronized` / `volatile`).
+  - `getSessionFactory()` throws if called before `start()`.
+  - Remove `JpaUtils.bind`.
+  - Add `hibernate.hbm2ddl.auto=validate` to `hibernate.cfg.xml` and map `OWebUser` there if it has a table.
+- **`DatabaseMigration`**: takes `DatabaseConfig`.
+- **Services** get their dependencies through constructors:
+  - `GuildService(String guildId, GuildRepository, BlacklistRepository, GuildSettingRepository)`.
+  - `updateDebugMode` becomes `oGuild = guildRepository.save(modified)`.
+  - `BlacklistService.reloadBlacklistCache` uses `findEnabledWords` (no `tryLoad`).
+  - `GuildSettingService` builds a new map and swaps it into a `volatile` field. `getSettings()` returns an unmodifiable view.
+  - `TaskService` receives `TaskRepository` and uses the field. It parses the payload once.
+- **`GuildServiceProvider` / `GuildServiceProviderImpl`** follow the ID-only API: the provider is constructed with the repositories, uses `ConcurrentHashMap.computeIfAbsent`, and has `evict` and `snapshot`.
+- **Callers updated to the new service API:**
+  - `BlacklistCommand` maps `BlacklistResult` to success/warn replies, passes `context.getGuildUser().getId()`, and lists entries through `list()`.
+  - `ConfigureCommand` uses `set(...)` / `snapshot()`.
+  - `MusicCommand`, `MusicManager`, `MusicServiceImpl`, `ActionRoutes`, `BotState`, `LoadPlaylistTask` and `TaskManagerImpl` use `get(String)` and `snapshot()`.
+  - `EventsHandler`: on `GuildLeaveEvent` it calls `deleteGuild()` and then `evict(id)`.
+- **`App.java`**:
+  - Build the repositories from the registered `SessionManager`.
+  - Pass them to `GuildServiceProviderImpl` and `TaskService`.
+  - Remove `JpaUtils.bindGuildServiceLookup`.
+  - Update the callers of `MessageRepository.log`.
+- **Entities**:
+  - Add ID-based `equals`/`hashCode` (with a null-safe `getClass`/proxy-aware pattern).
+  - Rename `OLoggings` to `loggings`.
+- **Cleanup**: fix the headers, standardize on the Log4j API, and document `GSettings`.
+
+### File Structure
+- **New**:
+  - `db/DatabaseConfig.java`
+  - `db/service/BlacklistResult.java`, `db/service/BlacklistEntry.java`
+  - `db/AbstractRepository.java` (replaces `db/Repository.java`)
+  - `src/test/java/me/bobert/netneutrality/db/**` tests
+- **Modified**:
+  - `SessionManager`, `SessionProvider` (if needed), `DatabaseMigration`
+  - all 5 repositories, all services, `GuildServiceProvider`
+  - the callers: `BlacklistCommand`, `ConfigureCommand`, `MusicCommand`, `MusicManager`, `MusicServiceImpl`, `EventsHandler`, `ActionRoutes`, `BotState`, `TaskManagerImpl`, `LoadPlaylistTask`
+  - the entities, `hibernate.cfg.xml`, `App.java`, `pom.xml` (test dependencies)
+- **Deleted**: `db/JpaUtils.java`, `db/Repository.java`.
+
+### Architecture Diagram
+```mermaid
+graph LR
+App --> SessionManager
+SessionManager -->|migrate first| DatabaseMigration
+SessionManager -->|builds| SF[SessionFactory]
+App --> Repos[AbstractRepository subclasses]
+Repos -->|fromTransaction| SF
+App --> GSP[GuildServiceProviderImpl]
+GSP --> GuildService
+GuildService --> BlacklistService
+GuildService --> GuildSettingService
+BlacklistService --> Repos
+GuildSettingService --> Repos
+App --> TaskService
+TaskService --> Repos
+```
+
+### Risks
+- **`validate` may fail on existing drift** between the entities and V1/V2. Mitigation: the integration test catches it; fix the mapping or add `V3__*.sql`.
+- **Callers relied on swallowed exceptions.** Commands such as `BlacklistCommand` and `ConfigureCommand` catch them and show a warning reply. The listener and `LogHandler` paths are reviewed so errors stay logged and don't crash event handling.
+- **Wide caller change set** from the API redesign. Mitigation: do it in its own stage, keep the method semantics identical, and rely on the compiler and `./mvnw test` to catch every call site.
+- **Lazy associations accessed outside a session** (for example `OGuild.getBlacklists()` elsewhere). Mitigation: search for the getters and replace them with repository queries.
+
+# Testing
+
+### Validation Approach
+- Run `./mvnw test` after each stage. Existing tests (for example `ApplicationContextTest`) must keep passing.
+- Add the `org.testcontainers:mysql` and `junit-jupiter` test dependencies.
+- Add a shared `MySqlTestBase` that:
+  - starts `mysql:8`
+  - builds a `DatabaseConfig` / `SettingsProvider` stub
+  - starts a real `SessionManager` (Flyway plus validate)
+  - uses `@Testcontainers(disabledWithoutDocker = true)`
+
+### Key Scenarios
+- `SessionManager` starts against the container: the migrations apply and schema validation passes.
+- `BlacklistRepository`: adding a word and then deleting it removes the row (regression for B1). Re-adding a disabled word re-enables it.
+- `GuildSettingRepository`: setting, updating and resetting to default each persist the expected state (regression for B2).
+- `AbstractRepository`: `findById` / `deleteById` work with `Integer` and `String` IDs (B3). A failing write throws and leaves no partial data (B4).
+- `GuildService.findOrCreateGuild` creates the guild once, and a second call returns the existing row.
+- `GuildSettingService`: readers never observe an empty cache during a reload (unit test with Mockito).
+- `BlacklistService` returns `ADDED`, then `ALREADY_EXISTS`, then `REMOVED`, then `NOT_FOUND` for the matching sequence of calls (container test).
+- `BlacklistCommand` maps each `BlacklistResult` (and a thrown exception) to the expected reply type (Mockito unit test).
+- `GuildServiceProviderImpl.evict` removes the cached service, and the next `get` builds a new one.
+- Architecture check: a test scans `db.service` / `db.repository` classes to confirm there are no `net.dv8tion.jda` or `core.command` imports (a simple source-scan test).
+
+### Edge Cases
+- `MessageRepository.findByMessageId` for an unknown ID returns empty (no NPE).
+- `SessionManager.getSessionFactory()` before `start()` throws `IllegalStateException`.
+- `TaskService.persistTask` with an unregistered type is a no-op.
+
+# Delivery Steps
+
+### ✓ Step 1: Rework session bootstrap and add a generic base repository
+SessionManager migrates first, then builds a validated SessionFactory, and repositories can extend a type-safe injected base class.
+
+- Add `db/DatabaseConfig` record built from the `MYSQL_*` settings. Use it in both `SessionManager` and `DatabaseMigration`.
+- `SessionManager.start()`:
+  - runs Flyway first
+  - then builds the factory eagerly and thread-safely
+  - keeps the Sentry/dev logic
+  - does not log the password
+- `getSessionFactory()` throws before `start()`.
+- Add `hibernate.hbm2ddl.auto=validate` to `hibernate.cfg.xml` and map `OWebUser` if it has a table.
+- Add `AbstractRepository<T, ID>`, which takes a `SessionProvider` and implements:
+  - `findAll`
+  - `findById` returning `Optional`
+  - `save` returning the merged entity
+  - `deleteById`
+  - `read`/`write` helpers built on `fromSession`/`fromTransaction`/`inTransaction`
+- Add the Testcontainers test dependencies and a `MySqlTestBase`, plus a startup and schema validation test.
+
+### ✓ Step 2: Migrate repositories onto the base class and fix persistence bugs
+All five repositories use injected sessions with correct ID types, and the blacklist and setting write bugs are fixed and covered by tests.
+
+- Convert `GuildRepository`, `BlacklistRepository`, `GuildSettingRepository`, `TaskRepository` and `MessageRepository` to `AbstractRepository` with proper ID types.
+- Blacklist:
+  - `enableWord` / `deleteWord` query and modify inside the same transaction (fixes the detached remove).
+  - Add `findEnabledWords(guildId)`.
+- Guild settings: `upsertOrDelete` runs in a transaction and queries the setting directly.
+- Messages:
+  - JDA-free `log(...)`
+  - `updateEditedMessage`
+  - `Optional` lookups
+  - ordered `findByUser`
+- Remove the swallowed-exception patterns and fix the duplicated headers and package lines.
+- Add repository integration tests for the blacklist, settings, ID types and rollback scenarios.
+
+### ✓ Step 3: Refactor services and wiring, and remove JpaUtils
+Services receive their repositories through constructors, caches are thread-safe, and the static `JpaUtils` and `Repository` classes are gone.
+
+- `GuildService`:
+  - takes its repositories through the constructor
+  - `updateDebugMode` uses `save`
+  - `findOrCreateGuild` handles missing guilds, replacing `tryLoad`
+- `BlacklistService` reloads its cache through `findEnabledWords`.
+- `GuildSettingService` swaps in a new cache map and exposes it unmodifiable.
+- `TaskService`:
+  - uses the injected `TaskRepository` field
+  - parses the payload once
+- `GuildServiceProviderImpl` is constructed with the repositories and uses `computeIfAbsent`. The API changes come in Step 4.
+- Update `App.java`:
+  - build the repositories from `SessionManager`
+  - remove `JpaUtils.bindGuildServiceLookup`
+  - update the `MessageRepository.log` callers
+- Delete `JpaUtils.java` and `Repository.java`. Replace any lazy-collection access outside a session with repository queries.
+- Add service tests: Mockito for the caches, and the container test for `findOrCreateGuild`.
+
+### ✓ Step 4: Decouple services from JDA and command types, and update callers
+Services expose JDA-free, ID-based domain APIs, and every caller maps domain results to replies.
+
+- Add `BlacklistResult` and `BlacklistEntry`. `BlacklistService.add/remove/list` take plain IDs and return domain results instead of `CommandExecutionResult`.
+- `GuildSettingService` exposes `set` / `get` / `snapshot`.
+- `GuildServiceProvider` becomes ID-only: remove `get(Guild)`, add `evict`, and replace `getServices` with `snapshot`.
+- Update the callers:
+  - `BlacklistCommand` maps results and exceptions to replies
+  - `ConfigureCommand`
+  - `MusicCommand`, `MusicManager`, `MusicServiceImpl`
+  - `ActionRoutes`, `BotState`
+  - `TaskManagerImpl`, `LoadPlaylistTask`
+  - `EventsHandler` evicts on guild leave
+- Add tests: the `BlacklistService` result sequence (container), `BlacklistCommand` reply mapping (Mockito), provider eviction, and the no-JDA-imports source scan.
+
+### ✓ Step 5: Entity and package hygiene
+Entities follow JPA best practices and the package uses consistent conventions, with the full test suite green.
+
+- Add ID-based, proxy-safe `equals`/`hashCode` to the entities.
+- Rename `OGuild.OLoggings` to `loggings`.
+- Standardize logging on the Log4j API across `db.service`.
+- Document the `GSettings` entries by resolving the TODO.
+- Re-run schema validation. If entity/schema drift shows up, add a `V3__*.sql` migration or fix the mapping.
+- Run `./mvnw test` to confirm the existing and new tests pass.

pom.xml

@@ -18,6 +18,7 @@
         <maven.compiler.source>25</maven.compiler.source>
         <maven.compiler.target>25</maven.compiler.target>
         <mockito.version>5.23.0</mockito.version>
+        <testcontainers.version>2.0.5</testcontainers.version>
     </properties>
 
     <build>
@@ -273,6 +274,18 @@
             <version>${mockito.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.testcontainers</groupId>
+            <artifactId>testcontainers-junit-jupiter</artifactId>
+            <version>${testcontainers.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.testcontainers</groupId>
+            <artifactId>testcontainers-mysql</artifactId>
+            <version>${testcontainers.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
 </project>

src/main/java/me/bobert/netneutrality/App.java

@@ -28,7 +28,10 @@ import me.bobert.netneutrality.core.thread.ExecutorProvider;
 import me.bobert.netneutrality.utils.SettingsProvider;
 import me.bobert.netneutrality.db.service.GuildServiceProvider;
 import me.bobert.netneutrality.utils.ChannelMessagePurger;
-import me.bobert.netneutrality.db.JpaUtils;
+import me.bobert.netneutrality.db.repository.BlacklistRepository;
+import me.bobert.netneutrality.db.repository.GuildRepository;
+import me.bobert.netneutrality.db.repository.GuildSettingRepository;
+import me.bobert.netneutrality.db.repository.TaskRepository;
 import me.bobert.netneutrality.utils.Settings;
 import me.bobert.netneutrality.http.WebModule;
 import net.dv8tion.jda.api.JDA;
@@ -114,9 +117,11 @@ public class App {
         // Allow ApplicationContext itself to be injected into components that need it.
         context.register(context);
 
-        // Persistence: build the SessionFactory + run migrations; released last on shutdown.
-        // SessionManager binds itself into JpaUtils for repository access.
-        context.register(new SessionManager(settings));
+        // Persistence: run migrations + build the SessionFactory; released last on shutdown.
+        SessionManager sessions = context.register(new SessionManager(settings));
+        GuildRepository guildRepository = new GuildRepository(sessions);
+        BlacklistRepository blacklistRepository = new BlacklistRepository(sessions);
+        GuildSettingRepository guildSettingRepository = new GuildSettingRepository(sessions);
 
         // Executors: no explicit start today; shut down after music players are disconnected.
         ExecutorProvider executors = context.register(new ThreadManager());
@@ -130,12 +135,12 @@ public class App {
         CommandRegistry commands = context.register(new CommandManager(context));
 
         // Task registry (priority 30).
-        TaskManager tasks = context.register(new TaskManagerImpl(context));
+        TaskManager tasks = context.register(new TaskManagerImpl(context, new TaskRepository(sessions)));
 
         // Per-guild service cache (not a Lifecycle component).
-        GuildServiceProvider guildServices = context.register(new GuildServiceProviderImpl());
+        GuildServiceProvider guildServices = context.register(
+            new GuildServiceProviderImpl(guildRepository, blacklistRepository, guildSettingRepository));
         LogHandler.bind(guildServices);
-        JpaUtils.bindGuildServiceLookup(guildServices::get);
 
         // Music sources (priority 40): initialise the shared player manager; disconnect on shutdown.
         music = context.register(new MusicServiceImpl(settings, guildServices, tasks, executors));

src/main/java/me/bobert/netneutrality/bootstrap/BotState.java

@@ -42,7 +42,7 @@ public class BotState {
             return;
         }
 
-        Map<String, GuildService> services = guildServices.getServices();
+        Map<String, GuildService> services = guildServices.snapshot();
 
         ObjectNode main = Json.object();
         ArrayNode guildsArray = Json.array();
@@ -56,7 +56,7 @@ public class BotState {
 
             ObjectNode guild = Json.object();
             ObjectNode music = Json.object();
-            guild.put("id", service.getEntity().getGuildId());
+            guild.put("id", service.getGuildId());
 
 //            MessageChannel currentChannel = trackScheduler.getTextChannel();
 //            if (currentChannel == null) {

src/main/java/me/bobert/netneutrality/command/admin/BlacklistCommand.java

@@ -10,16 +10,20 @@ import me.bobert.netneutrality.core.command.CommandOptionsBuilder;
 import me.bobert.netneutrality.core.command.impl.AdminCommand;
 import me.bobert.netneutrality.core.command.options.CommandOption;
 import me.bobert.netneutrality.core.context.CommandContext;
-import me.bobert.netneutrality.db.entities.OBlacklist;
+import me.bobert.netneutrality.db.service.BlacklistEntry;
+import me.bobert.netneutrality.db.service.BlacklistResult;
 import me.bobert.netneutrality.db.service.BlacklistService;
+import me.bobert.netneutrality.db.service.GuildServiceProvider;
 import net.dv8tion.jda.api.interactions.commands.OptionType;
 import net.dv8tion.jda.api.interactions.commands.build.SubcommandData;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 
 import java.util.List;
 import java.util.Objects;
-import me.bobert.netneutrality.db.service.GuildServiceProvider;
 
 public class BlacklistCommand extends AdminCommand {
+    private static final Logger logger = LogManager.getLogger(BlacklistCommand.class);
 
     private final GuildServiceProvider guildServices;
 
@@ -64,16 +68,16 @@ public class BlacklistCommand extends AdminCommand {
     public CommandExecutionResult execute(CommandContext context) {
         String sub = context.getSubcommand();
         String word = context.getOption("word", "", CommandOption::getAsString);
-        BlacklistService service = guildServices.get(context.getGuild()).getBlacklistService();
+        BlacklistService service = guildServices.get(context.getGuild().getId()).getBlacklistService();
 
         switch (sub) {
             case "get" -> context.async("Retrieving list, please wait...", asyncMessage -> {
-                List<OBlacklist> blacklists = service.getBlacklistForGuild();
+                List<BlacklistEntry> blacklists = service.list();
 
                 StringBuilder sb = new StringBuilder();
                 sb.append("List of blacklisted words for this server: \n");
-                for (OBlacklist bl : blacklists) {
-                    sb.append(bl.getWord()).append(" -> ").append(bl.getEnabled() ? "enabled" : "disabled").append("\n");
+                for (BlacklistEntry bl : blacklists) {
+                    sb.append(bl.word()).append(" -> ").append(bl.enabled() ? "enabled" : "disabled").append("\n");
                 }
 
                 if (blacklists.isEmpty()) {
@@ -83,13 +87,32 @@ public class BlacklistCommand extends AdminCommand {
                 asyncMessage.edit(sb.toString());
             });
             case "add" -> {
-                return service.add(context.getGuildUser(), word);
+                try {
+                    return toReply(service.add(context.getGuildUser().getId(), word), word);
+                } catch (RuntimeException e) {
+                    logger.error("Failed to add word to blacklist", e);
+                    return CommandExecutionResult.warn("Failed to add word to blacklist: " + e.getMessage());
+                }
             }
             case "remove" -> {
-                return service.delete(word);
+                try {
+                    return toReply(service.remove(word), word);
+                } catch (RuntimeException e) {
+                    logger.error("Failed to remove word from blacklist", e);
+                    return CommandExecutionResult.warn("Failed to remove word from blacklist: " + e.getMessage());
+                }
             }
         }
 
         return CommandExecutionResult.none();
     }
+
+    static CommandExecutionResult toReply(BlacklistResult result, String word) {
+        return switch (result) {
+            case ADDED, REENABLED -> CommandExecutionResult.success("Added the word [%s] to the blacklist.", word);
+            case ALREADY_EXISTS -> CommandExecutionResult.warn(String.format("The word [%s] is already in the blacklist.", word));
+            case REMOVED -> CommandExecutionResult.success("Removed the word [%s] from the blacklist.", word);
+            case NOT_FOUND -> CommandExecutionResult.warn(String.format("The word [%s] is not in the blacklist.", word));
+        };
+    }
 }

src/main/java/me/bobert/netneutrality/command/bot/ConfigureCommand.java

@@ -12,19 +12,23 @@ import me.bobert.netneutrality.core.command.options.CommandOption;
 import me.bobert.netneutrality.core.context.CommandContext;
 import me.bobert.netneutrality.db.GSettings;
 import me.bobert.netneutrality.db.service.GuildService;
+import me.bobert.netneutrality.db.service.GuildSettingService;
 import net.dv8tion.jda.api.entities.Role;
 import net.dv8tion.jda.api.entities.channel.concrete.TextChannel;
 import net.dv8tion.jda.api.entities.channel.unions.GuildChannelUnion;
 import net.dv8tion.jda.api.interactions.commands.OptionType;
 import net.dv8tion.jda.api.interactions.commands.build.OptionData;
 import net.dv8tion.jda.api.interactions.commands.build.SubcommandData;
-import net.dv8tion.jda.api.utils.messages.MessageCreateBuilder;
-
-import java.util.Map;
 import me.bobert.netneutrality.db.service.GuildServiceProvider;
 import me.bobert.netneutrality.music.MusicService;
+import net.dv8tion.jda.api.utils.messages.MessageCreateBuilder;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.util.Map;
 
 public class ConfigureCommand extends AdminCommand {
+    private static final Logger logger = LogManager.getLogger(ConfigureCommand.class);
 
     private final GuildServiceProvider guildServices;
     private final MusicService musicService;
@@ -76,8 +80,18 @@ public class ConfigureCommand extends AdminCommand {
 
     @Override
     public CommandExecutionResult execute(CommandContext context) {
+        try {
+            return configure(context);
+        } catch (RuntimeException e) {
+            logger.error("Failed to update configuration", e);
+            return CommandExecutionResult.warn("Failed to update configuration: " + e.getMessage());
+        }
+    }
+
+    private CommandExecutionResult configure(CommandContext context) {
         String sub = context.getSubcommand();
         GuildService guildService = guildServices.get(context.getGuild().getId());
+        GuildSettingService settingService = guildService.getGuildSettingService();
         context.ephemeral();
 
         if ("music-role".equals(sub)) {
@@ -85,13 +99,13 @@ public class ConfigureCommand extends AdminCommand {
             assert role != null;
 
             if (role.getPosition() == -1) {
-                guildService.getGuildSettingService().setSettingValue(GSettings.MUSIC_ROLE, null);
+                settingService.set(GSettings.MUSIC_ROLE, null);
 
                 return CommandExecutionResult.success("Everyone can now use music commands");
             }
 
             if (role.getGuild().getId().equals(context.getGuild().getId())) {
-                guildService.getGuildSettingService().setSettingValue(GSettings.MUSIC_ROLE, role.getId());
+                settingService.set(GSettings.MUSIC_ROLE, role.getId());
 
                 return CommandExecutionResult.success(String.format("Successfully set %s as the role needed for music command", role.getAsMention()));
             }
@@ -101,14 +115,14 @@ public class ConfigureCommand extends AdminCommand {
             GuildChannelUnion channel = context.getOption("channel", CommandOption::getAsChannel);
 
             if (channel == null) {
-                guildService.getGuildSettingService().setSettingValue(GSettings.MUSIC_CHANNEL, null);
+                settingService.set(GSettings.MUSIC_CHANNEL, null);
 
                 return CommandExecutionResult.success("No channel restrictions for music commands");
             }
 
             if (channel instanceof TextChannel) {
                 if (channel.getGuild().getId().equals(context.getGuild().getId())) {
-                    guildService.getGuildSettingService().setSettingValue(GSettings.MUSIC_CHANNEL, channel.getId());
+                    settingService.set(GSettings.MUSIC_CHANNEL, channel.getId());
 
                     return CommandExecutionResult.success(String.format("Successfully set %s as the channel required to execute music command", channel.getAsMention()));
                 }
@@ -118,7 +132,7 @@ public class ConfigureCommand extends AdminCommand {
 
         if ("music-volume".equals(sub)) {
             int volume = context.getOption("volume", 30, CommandOption::getAsInt);
-            guildService.getGuildSettingService().setSettingValue(GSettings.MUSIC_VOLUME, String.valueOf(volume));
+            settingService.set(GSettings.MUSIC_VOLUME, String.valueOf(volume));
             musicService.get(context.getGuild()).setVolume(volume);
 
             return CommandExecutionResult.success(String.format("Default volume for music player is now %d", volume));
@@ -132,7 +146,7 @@ public class ConfigureCommand extends AdminCommand {
         }
 
         if ("show-all".equals(sub)) {
-            Map<String, String> settings = guildService.getGuildSettingService().getSettings();
+            Map<String, String> settings = settingService.snapshot();
             MessageCreateBuilder builder = new MessageCreateBuilder();
 
             for (GSettings o : GSettings.values()) {

src/main/java/me/bobert/netneutrality/core/LogHandler.java

@@ -92,7 +92,7 @@ public class LogHandler {
 
         if (context.getGuild() != null) {
             GuildServiceProvider provider = guildServices;
-            if (provider != null && provider.get(context.getGuild()).isDebugEnabled()) {
+            if (provider != null && provider.get(context.getGuild().getId()).isDebugEnabled()) {
                 context.getGuild()
                     .getTextChannels()
                     .stream()

src/main/java/me/bobert/netneutrality/core/command/impl/MusicCommand.java

@@ -43,7 +43,7 @@ public abstract class MusicCommand extends AbstractCommand {
      * @return the guild service
      */
     protected final GuildService guildService(Guild guild) {
-        return guildServices.get(guild);
+        return guildServices.get(guild.getId());
     }
 
     /**
@@ -79,7 +79,7 @@ public abstract class MusicCommand extends AbstractCommand {
 
         Guild guild = member.getGuild();
 
-        String roleDb = guildService(guild.getId()).getGuildSettingService().getSetting(GSettings.MUSIC_ROLE);
+        String roleDb = guildService(guild.getId()).getGuildSettingService().getOrDefault(GSettings.MUSIC_ROLE);
 
         if (roleDb != null && !roleDb.isEmpty()) {
             if (UserFunction.isAdmin(member)) {
@@ -89,7 +89,7 @@ public abstract class MusicCommand extends AbstractCommand {
             Role neededRole = guild.getRoleById(roleDb);
             if (neededRole == null) {
                 // Role doesn't exist on guild anymore, remove from db
-                guildService(guild.getId()).getGuildSettingService().setSettingValue(GSettings.MUSIC_ROLE, null);
+                guildService(guild.getId()).getGuildSettingService().set(GSettings.MUSIC_ROLE, null);
                 return true;
             }
 
@@ -106,7 +106,7 @@ public abstract class MusicCommand extends AbstractCommand {
                 return false;
             }
 
-            String channelDb = guildService(guildMessageChannel.getGuild()).getGuildSettingService().getSetting(GSettings.MUSIC_CHANNEL);
+            String channelDb = guildService(guildMessageChannel.getGuild()).getGuildSettingService().getOrDefault(GSettings.MUSIC_CHANNEL);
             if (channelDb != null && !channelDb.isEmpty()) {
                 return channelDb.equals(channel.getId());
             }

src/main/java/me/bobert/netneutrality/core/tasks/TaskManagerImpl.java

@@ -16,6 +16,7 @@ import me.bobert.netneutrality.core.tasks.trait.WithButton;
 import me.bobert.netneutrality.core.tasks.trait.WithChildren;
 import me.bobert.netneutrality.core.tasks.trait.WithParent;
 import me.bobert.netneutrality.core.tasks.persistence.PersistableTaskRegistry;
+import me.bobert.netneutrality.db.repository.TaskRepository;
 import me.bobert.netneutrality.db.service.TaskService;
 import me.bobert.netneutrality.exceptions.GracefulContextError;
 import me.bobert.netneutrality.exceptions.TaskExecutionException;
@@ -52,9 +53,10 @@ public class TaskManagerImpl implements TaskManager {
      * Creates a task manager that can inject context-registered dependencies into reflectively
      * loaded tasks.
      *
-     * @param context the application context; must not be {@code null}
+     * @param context        the application context; must not be {@code null}
+     * @param taskRepository the repository persisting {@link PersistableTask}s
      */
-    public TaskManagerImpl(ApplicationContext context) {
+    public TaskManagerImpl(ApplicationContext context, TaskRepository taskRepository) {
         Objects.requireNonNull(context, "ApplicationContext must not be null");
         this.tasks = new ConcurrentHashMap<>();
         this.pendingTasks = new ConcurrentHashMap<>();
@@ -62,7 +64,7 @@ public class TaskManagerImpl implements TaskManager {
         this.tasksLock = new ConcurrentHashMap<>();
         this.context = context;
         this.persistableTaskRegistry = new PersistableTaskRegistry(context);
-        this.taskService = new TaskService(this, persistableTaskRegistry);
+        this.taskService = new TaskService(this, persistableTaskRegistry, taskRepository);
     }
 
     @Override

src/main/java/me/bobert/netneutrality/db/AbstractRepository.java

@@ -0,0 +1,95 @@
+package me.bobert.netneutrality.db;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import jakarta.persistence.criteria.CriteriaQuery;
+import org.hibernate.Session;
+
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.function.Consumer;
+import java.util.function.Function;
+
+/**
+ * Generic, constructor-injected Hibernate repository.
+ *
+ * <p>All work runs through Hibernate's native {@code fromSession}/{@code fromTransaction}/
+ * {@code inTransaction} helpers, which open and close the session and commit or roll back the
+ * transaction. Exceptions are never swallowed: a failed write is rolled back and rethrown.
+ *
+ * @param <T>  the entity type
+ * @param <ID> the entity identifier type
+ */
+public abstract class AbstractRepository<T, ID> {
+
+    protected final SessionProvider sessions;
+    private final Class<T> type;
+
+    protected AbstractRepository(SessionProvider sessions, Class<T> type) {
+        this.sessions = Objects.requireNonNull(sessions, "sessions");
+        this.type = Objects.requireNonNull(type, "type");
+    }
+
+    protected Class<T> type() {
+        return type;
+    }
+
+    public List<T> findAll() {
+        return read(session -> {
+            CriteriaQuery<T> query = session.getCriteriaBuilder().createQuery(type);
+            query.from(type);
+            return session.createSelectionQuery(query).getResultList();
+        });
+    }
+
+    public Optional<T> findById(ID id) {
+        Objects.requireNonNull(id, "id");
+        return read(session -> Optional.ofNullable(session.find(type, id)));
+    }
+
+    /**
+     * Inserts or updates the entity.
+     *
+     * @param entity the entity to save
+     * @return the persistent (merged) state, which callers should use from then on
+     */
+    public T save(T entity) {
+        Objects.requireNonNull(entity, "entity");
+        return write(session -> session.merge(entity));
+    }
+
+    /**
+     * Deletes the entity with the given id, if it exists.
+     *
+     * @param id the identifier
+     * @return {@code true} if a row was deleted
+     */
+    public boolean deleteById(ID id) {
+        Objects.requireNonNull(id, "id");
+        return write(session -> {
+            T entity = session.find(type, id);
+            if (entity == null) {
+                return false;
+            }
+            session.remove(entity);
+            return true;
+        });
+    }
+
+    protected <R> R read(Function<Session, R> work) {
+        return sessions.getSessionFactory().fromSession(work);
+    }
+
+    protected <R> R write(Function<Session, R> work) {
+        return sessions.getSessionFactory().fromTransaction(work);
+    }
+
+    protected void writeVoid(Consumer<Session> work) {
+        sessions.getSessionFactory().inTransaction(work);
+    }
+}

src/main/java/me/bobert/netneutrality/db/DatabaseConfig.java

@@ -0,0 +1,48 @@
+package me.bobert.netneutrality.db;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import me.bobert.netneutrality.utils.SettingsProvider;
+
+import java.util.Objects;
+
+/**
+ * JDBC connection settings shared by Flyway ({@link DatabaseMigration}) and Hibernate
+ * ({@link SessionManager}), so both always connect to the same database.
+ *
+ * @param url      the JDBC url
+ * @param user     the database user
+ * @param password the database password (never logged, see {@link #toString()})
+ */
+public record DatabaseConfig(String url, String user, String password) {
+
+    public DatabaseConfig {
+        Objects.requireNonNull(url, "url");
+        Objects.requireNonNull(user, "user");
+        password = password == null ? "" : password;
+    }
+
+    /**
+     * Builds the config from the {@code MYSQL_*} settings.
+     *
+     * @param settings the bot settings
+     * @return the database config
+     */
+    public static DatabaseConfig from(SettingsProvider settings) {
+        String dbName = settings.get("MYSQL_DATABASE", "netneutrality");
+        String dbUser = settings.get("MYSQL_USER", "root");
+        String dbPass = settings.get("MYSQL_PASSWORD", "");
+        String dbHost = settings.get("MYSQL_HOST", "localhost");
+        String dbPort = settings.get("MYSQL_PORT", "3306");
+        return new DatabaseConfig(String.format("jdbc:mysql://%s:%s/%s", dbHost, dbPort, dbName), dbUser, dbPass);
+    }
+
+    @Override
+    public String toString() {
+        return "DatabaseConfig[url=" + url + ", user=" + user + ", password=***]";
+    }
+}

src/main/java/me/bobert/netneutrality/db/DatabaseMigration.java

@@ -1,37 +1,38 @@
 package me.bobert.netneutrality.db;
+
 /*
  * Copyright (c) anthorob
  *
  * https://discord.gg/qUa6zNFZsd
  */
 
-import me.bobert.netneutrality.utils.SettingsProvider;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.flywaydb.core.Flyway;
 import org.flywaydb.core.api.output.MigrateResult;
 
-public class DatabaseMigration {
-    private final static Logger logger = LogManager.getLogger(DatabaseMigration.class);
+public final class DatabaseMigration {
+    private static final Logger logger = LogManager.getLogger(DatabaseMigration.class);
 
-    public static void migrate(SettingsProvider settings) {
-        String dbName = settings.get("MYSQL_DATABASE", "netneutrality");
-        String dbUser = settings.get("MYSQL_USER", "root");
-        String dbPass = settings.get("MYSQL_PASSWORD", "");
-        String dbHost = settings.get("MYSQL_HOST", "localhost");
-        String dbPort = settings.get("MYSQL_PORT", "3306");
-        String dbUrl = String.format("jdbc:mysql://%s:%s/%s", dbHost, dbPort, dbName);
+    private DatabaseMigration() {
+    }
 
+    /**
+     * Applies all pending Flyway migrations to the configured database.
+     *
+     * @param config the database connection settings
+     * @throws IllegalStateException if the migration fails
+     */
+    public static void migrate(DatabaseConfig config) {
         try {
             logger.info("Running database migrations..");
             Flyway flyway = Flyway.configure()
-                .dataSource(dbUrl, dbUser, dbPass)
+                .dataSource(config.url(), config.user(), config.password())
                 .load();
 
             MigrateResult result = flyway.migrate();
             logger.info("Database migrations finished successfully! (total: {})", result.migrationsExecuted);
         } catch (Exception e) {
-            logger.error(e);
             throw new IllegalStateException("Database migration failed", e);
         }
     }

src/main/java/me/bobert/netneutrality/db/GSettings.java

@@ -1,15 +1,26 @@
 package me.bobert.netneutrality.db;
+
 /*
  * Copyright (c) anthorob
  *
  * https://discord.gg/qUa6zNFZsd
  */
 
+/**
+ * Per-guild settings stored in the {@code guild_settings} table.
+ *
+ * <p>Only values that differ from the default are stored; setting a value back to its default (or
+ * {@code null}) deletes the row. {@link #getName()} is the key persisted in the {@code name}
+ * column and must never change for an existing setting.
+ */
 public enum GSettings {
-    //TODO: description
+    /** Id of the role required to use music commands; empty means everyone may use them. */
     MUSIC_ROLE("MUSIC_ROLE", ""),
+    /** Id of the only text channel music commands may be used in; empty means any channel. */
     MUSIC_CHANNEL("MUSIC_CHANNEL", ""),
+    /** Default playback volume (0-100) applied when a music player is created. */
     MUSIC_VOLUME("MUSIC_VOLUME", "30"),
+    /** Playlist size above which the bot asks for confirmation before queueing every track. */
     MUSIC_MAXPLAYLISTSIZE("MUSIC_MAXPLAYLISTSIZE", "20");
 
     private final String name;

src/main/java/me/bobert/netneutrality/db/JpaUtils.java

@@ -1,158 +0,0 @@
-package me.bobert.netneutrality.db;
-
-/*
- * Copyright (c) anthorob
- *
- * https://discord.gg/qUa6zNFZsd
- */
-
-import me.bobert.netneutrality.db.entities.OGuild;
-import me.bobert.netneutrality.db.service.GuildService;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
-import org.hibernate.HibernateException;
-import org.hibernate.ObjectNotFoundException;
-import org.hibernate.Session;
-import org.hibernate.SessionFactory;
-import org.hibernate.Transaction;
-import org.hibernate.exception.ConstraintViolationException;
-
-import java.io.Serializable;
-import java.util.Objects;
-import java.util.function.Consumer;
-import java.util.function.Function;
-
-/**
- * Static Hibernate helpers used by repositories and domain services.
- *
- * <p>Because repositories are created deep in the object graph without constructor injection,
- * this class holds a single {@link SessionProvider} bound once during bootstrap via
- * {@link #bind(SessionProvider)}. That is the only global access point for sessions — there is no
- * {@code SessionManager.instance()} shim.
- */
-public class JpaUtils {
-
-    private static final Logger logger = LogManager.getLogger(JpaUtils.class);
-    private static volatile SessionProvider sessions;
-    private static volatile Function<String, GuildService> guildServiceLookup;
-
-    private JpaUtils() {
-    }
-
-    /**
-     * Binds the application {@link SessionProvider}. Called once from {@code SessionManager}'s
-     * constructor during context registration.
-     *
-     * @param provider the live session provider
-     */
-    public static void bind(SessionProvider provider) {
-        sessions = Objects.requireNonNull(provider, "SessionProvider");
-    }
-
-    /**
-     * Optional guild-service lookup used when recovering a missing {@link OGuild} entity. Bound from
-     * bootstrap once the {@code GuildServiceProvider} is available.
-     *
-     * @param lookup guild-id → service resolver
-     */
-    public static void bindGuildServiceLookup(Function<String, GuildService> lookup) {
-        guildServiceLookup = Objects.requireNonNull(lookup, "guildServiceLookup");
-    }
-
-    private static SessionFactory factory() {
-        SessionProvider provider = sessions;
-        if (provider == null) {
-            throw new IllegalStateException("JpaUtils has not been bound to a SessionProvider");
-        }
-        return provider.getSessionFactory();
-    }
-
-    /**
-     * Tries to read the persistent state into the object.
-     * <p>
-     * If the object is not found in the database and is of type {@link OGuild}, tries to recreate entity and throws
-     * an exception to block execution.
-     * <p>
-     *
-     * @param session The session in which to load the persistent object
-     * @param object  The persistent object
-     * @param id      Identifier
-     */
-    public static void tryLoad(Session session, Object object, Serializable id) {
-        try {
-            session.load(object, id);
-        } catch (HibernateException exception) {
-            if (exception instanceof ObjectNotFoundException) {
-                if (object instanceof OGuild oGuild) {
-                    String cachedId = oGuild.getGuildId();
-                    logger.error("Trying to load Guild[{}] while entity doesn't exist in database, reloading..", cachedId);
-
-                    Function<String, GuildService> lookup = guildServiceLookup;
-                    if (lookup == null) {
-                        session.close();
-                        throw exception;
-                    }
-                    GuildService service = lookup.apply(cachedId);
-                    service.reloadEntity();
-                    service.getBlacklistService().removeGuildBlacklist();
-                    logger.info("Guild[{}] reloaded", cachedId);
-                }
-            }
-
-            session.close();
-            throw exception;
-        }
-    }
-
-    public static Session openSession() {
-        return factory().openSession();
-    }
-
-    public static void runWithSession(Consumer<Session> consumer) {
-        try (Session session = factory().openSession()) {
-            consumer.accept(session);
-        }
-    }
-
-    public static void runWithTransaction(Consumer<Session> consumer) {
-        try (Session session = factory().openSession()) {
-            session.beginTransaction();
-            consumer.accept(session);
-            session.getTransaction().commit();
-        }
-    }
-
-    public static void updateWithTransaction(Object persistantEntity, Runnable runnable) {
-        try (Session session = factory().openSession()) {
-            Transaction transaction = session.beginTransaction();
-
-            try {
-                runnable.run();
-
-                session.merge(persistantEntity);
-                transaction.commit();
-            } catch (ConstraintViolationException e) {
-                logger.error(e);
-                throw e;
-            } catch (Exception e) {
-                logger.error(e);
-                transaction.rollback();
-            }
-        }
-    }
-
-    /**
-     * Loads the entity and relations from the database and executes the given consumer.
-     * This will load all Lazy relationships defined in the entity.
-     *
-     * @param persistantEntity The entity to load
-     * @param id               The identifier for the entity
-     * @param consumer         The comsumer, which exposes the session
-     */
-    public static void getWithSession(Object persistantEntity, Serializable id, Consumer<Session> consumer) {
-        try (Session session = factory().openSession()) {
-            tryLoad(session, persistantEntity, id);
-            consumer.accept(session);
-        }
-    }
-}

src/main/java/me/bobert/netneutrality/db/Repository.java

@@ -1,43 +0,0 @@
-package me.bobert.netneutrality.db;
-/*
- * Copyright (c) anthorob
- *
- * https://discord.gg/qUa6zNFZsd
- */
-
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
-import org.hibernate.Session;
-import org.hibernate.Transaction;
-import org.hibernate.exception.ConstraintViolationException;
-
-import java.util.List;
-
-public interface Repository<O> {
-    Logger logger = LogManager.getLogger(Repository.class);
-
-    List<O> findAll();
-
-    O findById(String id);
-
-    default void save(O entity) {
-        Transaction transaction = null;
-
-        try (Session session = JpaUtils.openSession()) {
-            transaction = session.beginTransaction();
-            session.merge(entity);
-            transaction.commit();
-        } catch (ConstraintViolationException e) {
-            logger.error(e);
-            throw e;
-        } catch (Exception e) {
-            logger.error(e);
-
-            if (transaction != null) {
-                transaction.rollback();
-            }
-        }
-    }
-
-    void deleteBy(String id);
-}

src/main/java/me/bobert/netneutrality/db/SessionManager.java

@@ -1,4 +1,5 @@
 package me.bobert.netneutrality.db;
+
 /*
  * Copyright (c) anthorob
  *
@@ -10,7 +11,6 @@ import me.bobert.netneutrality.utils.SettingsProvider;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.hibernate.SessionFactory;
-import org.hibernate.boot.Metadata;
 import org.hibernate.boot.MetadataSources;
 import org.hibernate.boot.registry.StandardServiceRegistry;
 import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
@@ -18,24 +18,34 @@ import org.hibernate.cfg.Environment;
 
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Objects;
 
 /**
  * Instance-based {@link SessionProvider} owning the Hibernate {@link SessionFactory} and its
  * service registry.
  *
- * <p>On construction the instance is bound into {@link JpaUtils} so repositories and other static
- * persistence helpers can open sessions without a global {@code SessionManager} singleton.
+ * <p>{@link #start()} first applies the Flyway migrations and only then builds the session factory,
+ * which validates the mapped entities against the migrated schema ({@code hbm2ddl.auto=validate}).
  */
 public class SessionManager implements SessionProvider {
     private static final Logger logger = LogManager.getLogger(SessionManager.class);
 
-    private final SettingsProvider settings;
+    private final DatabaseConfig config;
+    private final boolean reportErrors;
     private StandardServiceRegistry registry;
-    private SessionFactory sessionFactory;
+    private volatile SessionFactory sessionFactory;
 
     public SessionManager(SettingsProvider settings) {
-        this.settings = settings;
-        JpaUtils.bind(this);
+        this(DatabaseConfig.from(settings), !"dev".equals(settings.get("NETNEUTRALITY_BOT_ENV", "dev")));
+    }
+
+    /**
+     * @param config       the database connection settings
+     * @param reportErrors whether startup failures are reported to Sentry
+     */
+    public SessionManager(DatabaseConfig config, boolean reportErrors) {
+        this.config = Objects.requireNonNull(config, "config");
+        this.reportErrors = reportErrors;
     }
 
     @Override
@@ -44,55 +54,58 @@ public class SessionManager implements SessionProvider {
     }
 
     @Override
-    public void start() {
-        getSessionFactory();
-        DatabaseMigration.migrate(settings);
+    public synchronized void start() {
+        if (sessionFactory != null) {
+            return;
+        }
+
+        try {
+            logger.info("Connecting to database '{}' with user '{}'", config.url(), config.user());
+            DatabaseMigration.migrate(config);
+            sessionFactory = buildSessionFactory();
+        } catch (RuntimeException e) {
+            if (reportErrors) {
+                Sentry.captureException(e);
+            }
+
+            stop();
+            logger.error("Error connecting to database. Shutting down..", e);
+            throw new IllegalStateException("Unable to connect to the database", e);
+        }
+    }
+
+    private SessionFactory buildSessionFactory() {
+        Map<String, Object> settings = new HashMap<>();
+        settings.put(Environment.JAKARTA_JDBC_URL, config.url());
+        settings.put(Environment.JAKARTA_JDBC_USER, config.user());
+        settings.put(Environment.JAKARTA_JDBC_PASSWORD, config.password());
+
+        registry = new StandardServiceRegistryBuilder()
+            .configure()
+            .applySettings(settings)
+            .build();
+        return new MetadataSources(registry).buildMetadata().buildSessionFactory();
     }
 
     @Override
-    public void stop() {
+    public synchronized void stop() {
+        SessionFactory factory = sessionFactory;
+        sessionFactory = null;
+        if (factory != null) {
+            factory.close();
+        }
         if (registry != null) {
             StandardServiceRegistryBuilder.destroy(registry);
             registry = null;
-            sessionFactory = null;
         }
     }
 
     @Override
     public SessionFactory getSessionFactory() {
-        if (sessionFactory == null) {
-            try {
-                StandardServiceRegistryBuilder registryBuilder = new StandardServiceRegistryBuilder().configure();
-                Map<String, Object> config = new HashMap<>();
-                String dbName = settings.get("MYSQL_DATABASE", "netneutrality");
-                String dbUser = settings.get("MYSQL_USER", "root");
-                String dbPass = settings.get("MYSQL_PASSWORD", "");
-                String dbHost = settings.get("MYSQL_HOST", "localhost");
-                String dbPort = settings.get("MYSQL_PORT", "3306");
-                logger.info("Connecting to database '{}' at {}:{} with user '{}'", dbName, dbHost, dbPort, dbUser);
-
-                config.put(Environment.JAKARTA_JDBC_URL, String.format("jdbc:mysql://%s:%s/%s", dbHost, dbPort, dbName));
-                config.put(Environment.JAKARTA_JDBC_USER, dbUser);
-                config.put(Environment.JAKARTA_JDBC_PASSWORD, dbPass);
-                registryBuilder.applySettings(config);
-
-                registry = registryBuilder.build();
-                MetadataSources sources = new MetadataSources(registry);
-                Metadata metadata = sources.getMetadataBuilder().build();
-                sessionFactory = metadata.getSessionFactoryBuilder().build();
-
-            } catch (Exception e) {
-                String env = settings.get("NETNEUTRALITY_BOT_ENV", "dev");
-                if (!"dev".equals(env)) {
-                    Sentry.captureException(e);
-                }
-
-                stop();
-                logger.error("Error connecting to database. Shutting down..");
-                throw new IllegalStateException("Unable to connect to the database", e);
-            }
+        SessionFactory factory = sessionFactory;
+        if (factory == null) {
+            throw new IllegalStateException("SessionManager has not been started");
         }
-
-        return sessionFactory;
+        return factory;
     }
 }

src/main/java/me/bobert/netneutrality/db/entities/OBlacklist.java

@@ -15,6 +15,9 @@ import jakarta.persistence.Id;
 import jakarta.persistence.JoinColumn;
 import jakarta.persistence.ManyToOne;
 import jakarta.persistence.Table;
+import org.hibernate.Hibernate;
+
+import java.util.Objects;
 
 @Entity
 @Table(name = "blacklist")
@@ -76,4 +79,26 @@ public class OBlacklist {
     public void setId(Integer id) {
         this.id = id;
     }
+
+    /**
+     * Identity is the database id: two instances are equal when they have the same non-null id,
+     * regardless of Hibernate proxies. Transient instances (no id yet) are only equal to themselves.
+     */
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || Hibernate.getClass(this) != Hibernate.getClass(o)) {
+            return false;
+        }
+        OBlacklist other = (OBlacklist) o;
+        return getId() != null && Objects.equals(getId(), other.getId());
+    }
+
+    @Override
+    public int hashCode() {
+        // Constant per class so the hash never changes when the id is assigned on persist.
+        return Hibernate.getClass(this).hashCode();
+    }
 }

src/main/java/me/bobert/netneutrality/db/entities/OGuild.java

@@ -11,9 +11,10 @@ import jakarta.persistence.Entity;
 import jakarta.persistence.Id;
 import jakarta.persistence.OneToMany;
 import jakarta.persistence.Table;
+import org.hibernate.Hibernate;
 
 import java.util.LinkedHashSet;
-import java.util.Optional;
+import java.util.Objects;
 import java.util.Set;
 
 @Entity
@@ -43,14 +44,14 @@ public class OGuild {
     private Set<OLogMessage> logMessages = new LinkedHashSet<>();
 
     @OneToMany(mappedBy = "guild")
-    private Set<OLogging> OLoggings = new LinkedHashSet<>();
+    private Set<OLogging> loggings = new LinkedHashSet<>();
 
     public Set<OLogging> getLoggings() {
-        return OLoggings;
+        return loggings;
     }
 
-    public void setLoggings(Set<OLogging> OLoggings) {
-        this.OLoggings = OLoggings;
+    public void setLoggings(Set<OLogging> loggings) {
+        this.loggings = loggings;
     }
 
     public Set<OLogMessage> getLogMessages() {
@@ -110,13 +111,25 @@ public class OGuild {
         this.guildId = guildId;
     }
 
-    public OGuildSetting getSettingByName(String name) {
-        Optional<OGuildSetting> setting = getGuildSettings()
-            .stream()
-            .filter(setting1 -> setting1.getName().equalsIgnoreCase(name))
-            .findFirst();
-
-        return setting.orElse(null);
+    /**
+     * Identity is the database id: two instances are equal when they have the same non-null id,
+     * regardless of Hibernate proxies. Transient instances (no id yet) are only equal to themselves.
+     */
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || Hibernate.getClass(this) != Hibernate.getClass(o)) {
+            return false;
+        }
+        OGuild other = (OGuild) o;
+        return getGuildId() != null && Objects.equals(getGuildId(), other.getGuildId());
     }
 
+    @Override
+    public int hashCode() {
+        // Constant per class so the hash never changes when the id is assigned on persist.
+        return Hibernate.getClass(this).hashCode();
+    }
 }

src/main/java/me/bobert/netneutrality/db/entities/OGuildSetting.java

@@ -13,11 +13,13 @@ import jakarta.persistence.GeneratedValue;
 import jakarta.persistence.GenerationType;
 import jakarta.persistence.Id;
 import jakarta.persistence.JoinColumn;
-import jakarta.persistence.Lob;
 import jakarta.persistence.ManyToOne;
 import jakarta.persistence.NamedQueries;
 import jakarta.persistence.NamedQuery;
 import jakarta.persistence.Table;
+import org.hibernate.Hibernate;
+
+import java.util.Objects;
 
 @Entity
 @Table(name = "guild_settings")
@@ -33,8 +35,7 @@ public class OGuildSetting {
     @Column(name = "name", nullable = false)
     private String name;
 
-    @Lob
-    @Column(name = "value", nullable = false)
+    @Column(name = "value", nullable = false, columnDefinition = "text")
     private String value;
 
     @ManyToOne(fetch = FetchType.LAZY, optional = false)
@@ -72,4 +73,26 @@ public class OGuildSetting {
     public void setId(Integer id) {
         this.id = id;
     }
+
+    /**
+     * Identity is the database id: two instances are equal when they have the same non-null id,
+     * regardless of Hibernate proxies. Transient instances (no id yet) are only equal to themselves.
+     */
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || Hibernate.getClass(this) != Hibernate.getClass(o)) {
+            return false;
+        }
+        OGuildSetting other = (OGuildSetting) o;
+        return getId() != null && Objects.equals(getId(), other.getId());
+    }
+
+    @Override
+    public int hashCode() {
+        // Constant per class so the hash never changes when the id is assigned on persist.
+        return Hibernate.getClass(this).hashCode();
+    }
 }

src/main/java/me/bobert/netneutrality/db/entities/OLogMessage.java

@@ -16,8 +16,10 @@ import jakarta.persistence.Id;
 import jakarta.persistence.JoinColumn;
 import jakarta.persistence.ManyToOne;
 import jakarta.persistence.Table;
+import org.hibernate.Hibernate;
 
 import java.time.Instant;
+import java.util.Objects;
 
 @Entity
 @Table(name = "log_message")
@@ -113,4 +115,26 @@ public class OLogMessage {
     public void setId(Integer id) {
         this.id = id;
     }
+
+    /**
+     * Identity is the database id: two instances are equal when they have the same non-null id,
+     * regardless of Hibernate proxies. Transient instances (no id yet) are only equal to themselves.
+     */
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || Hibernate.getClass(this) != Hibernate.getClass(o)) {
+            return false;
+        }
+        OLogMessage other = (OLogMessage) o;
+        return getId() != null && Objects.equals(getId(), other.getId());
+    }
+
+    @Override
+    public int hashCode() {
+        // Constant per class so the hash never changes when the id is assigned on persist.
+        return Hibernate.getClass(this).hashCode();
+    }
 }

src/main/java/me/bobert/netneutrality/db/entities/OLogging.java

@@ -14,6 +14,9 @@ import jakarta.persistence.JoinColumn;
 import jakarta.persistence.ManyToOne;
 import jakarta.persistence.MapsId;
 import jakarta.persistence.Table;
+import org.hibernate.Hibernate;
+
+import java.util.Objects;
 
 @Entity
 @Table(name = "logging")
@@ -52,4 +55,26 @@ public class OLogging {
     public void setId(OLoggingId id) {
         this.id = id;
     }
+
+    /**
+     * Identity is the database id: two instances are equal when they have the same non-null id,
+     * regardless of Hibernate proxies. Transient instances (no id yet) are only equal to themselves.
+     */
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || Hibernate.getClass(this) != Hibernate.getClass(o)) {
+            return false;
+        }
+        OLogging other = (OLogging) o;
+        return getId() != null && Objects.equals(getId(), other.getId());
+    }
+
+    @Override
+    public int hashCode() {
+        // Constant per class so the hash never changes when the id is assigned on persist.
+        return Hibernate.getClass(this).hashCode();
+    }
 }

src/main/java/me/bobert/netneutrality/db/entities/OTask.java

@@ -10,9 +10,11 @@ import jakarta.persistence.Entity;
 import jakarta.persistence.GeneratedValue;
 import jakarta.persistence.GenerationType;
 import jakarta.persistence.Id;
-import jakarta.persistence.Lob;
 import jakarta.persistence.Table;
 import jakarta.persistence.UniqueConstraint;
+import org.hibernate.Hibernate;
+
+import java.util.Objects;
 
 @Entity
 @Table(name = "tasks", uniqueConstraints = {@UniqueConstraint(columnNames = {"task_id"})})
@@ -31,8 +33,7 @@ public class OTask {
     @Column(name = "task_class", nullable = false)
     private String taskClass;
 
-    @Lob
-    @Column(name = "payload")
+    @Column(name = "payload", columnDefinition = "text")
     private String payload;
 
     public Integer getId() {
@@ -67,4 +68,25 @@ public class OTask {
         this.payload = payload;
     }
 
+    /**
+     * Identity is the database id: two instances are equal when they have the same non-null id,
+     * regardless of Hibernate proxies. Transient instances (no id yet) are only equal to themselves.
+     */
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || Hibernate.getClass(this) != Hibernate.getClass(o)) {
+            return false;
+        }
+        OTask other = (OTask) o;
+        return getId() != null && Objects.equals(getId(), other.getId());
+    }
+
+    @Override
+    public int hashCode() {
+        // Constant per class so the hash never changes when the id is assigned on persist.
+        return Hibernate.getClass(this).hashCode();
+    }
 }

src/main/java/me/bobert/netneutrality/db/entities/OWebUser.java

@@ -9,11 +9,12 @@ package me.bobert.netneutrality.db.entities;
 import jakarta.persistence.Column;
 import jakarta.persistence.Entity;
 import jakarta.persistence.Id;
-import jakarta.persistence.Lob;
 import jakarta.persistence.Table;
 import org.hibernate.annotations.ColumnDefault;
+import org.hibernate.Hibernate;
 
 import java.time.Instant;
+import java.util.Objects;
 
 @Entity
 @Table(name = "web_users")
@@ -22,8 +23,7 @@ public class OWebUser {
     @Column(name = "id", nullable = false)
     private String id;
 
-    @Lob
-    @Column(name = "email", nullable = false)
+    @Column(name = "email", nullable = false, columnDefinition = "mediumtext")
     private String email;
 
     @Column(name = "token", nullable = false)
@@ -87,4 +87,25 @@ public class OWebUser {
         this.rememberToken = rememberToken;
     }
 
+    /**
+     * Identity is the database id: two instances are equal when they have the same non-null id,
+     * regardless of Hibernate proxies. Transient instances (no id yet) are only equal to themselves.
+     */
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null || Hibernate.getClass(this) != Hibernate.getClass(o)) {
+            return false;
+        }
+        OWebUser other = (OWebUser) o;
+        return getId() != null && Objects.equals(getId(), other.getId());
+    }
+
+    @Override
+    public int hashCode() {
+        // Constant per class so the hash never changes when the id is assigned on persist.
+        return Hibernate.getClass(this).hashCode();
+    }
 }

src/main/java/me/bobert/netneutrality/db/repository/BlacklistRepository.java

@@ -1,104 +1,107 @@
 package me.bobert.netneutrality.db.repository;
+
 /*
  * Copyright (c) anthorob
  *
  * https://discord.gg/qUa6zNFZsd
  */
 
-import me.bobert.netneutrality.db.Repository;
+import me.bobert.netneutrality.db.AbstractRepository;
+import me.bobert.netneutrality.db.SessionProvider;
 import me.bobert.netneutrality.db.entities.OBlacklist;
 import me.bobert.netneutrality.db.entities.OGuild;
-import me.bobert.netneutrality.db.JpaUtils;
-import net.dv8tion.jda.api.entities.Member;
 import org.hibernate.Session;
-import org.hibernate.query.Query;
 
-import java.util.ArrayList;
 import java.util.List;
+import java.util.Set;
+import java.util.stream.Collectors;
 
-public class BlacklistRepository implements Repository<OBlacklist> {
+public class BlacklistRepository extends AbstractRepository<OBlacklist, Integer> {
 
-    @Override
-    public List<OBlacklist> findAll() {
-        List<OBlacklist> blacklists = new ArrayList<>();
-
-        JpaUtils.runWithSession(session -> {
-            Query<OBlacklist> query = session.createQuery("FROM OBlacklist", OBlacklist.class);
-
-            blacklists.addAll(query.list());
-        });
-
-        return blacklists;
+    /**
+     * Outcome of {@link #enableWord(String, String, String)}.
+     */
+    public enum EnableOutcome {
+        /** A new row was inserted. */
+        CREATED,
+        /** An existing, disabled row was re-enabled. */
+        ENABLED,
+        /** The word was already enabled. */
+        UNCHANGED
     }
 
-    @Override
-    public OBlacklist findById(String id) {
-        return null;
-    }
-
-    @Override
-    public void deleteBy(String id) {
-        JpaUtils.runWithTransaction(session -> {
-            Query<OBlacklist> query = session.createQuery("SELECT o FROM OBlacklist o WHERE o.id = :blacklistId", OBlacklist.class);
-            query.setParameter("blacklistId", id);
-
-            OBlacklist oTask = query.uniqueResult();
-            if (oTask != null) {
-                session.remove(oTask);
-            }
-        });
+    public BlacklistRepository(SessionProvider sessions) {
+        super(sessions, OBlacklist.class);
     }
 
     public List<OBlacklist> findByGuildId(String guildId) {
-        List<OBlacklist> blacklists = new ArrayList<>();
-
-        JpaUtils.runWithSession(session -> {
-            Query<OBlacklist> query = session.createQuery("SELECT o FROM OBlacklist o WHERE o.guild.guildId = :guildId", OBlacklist.class);
-            query.setParameter("guildId", guildId);
-
-            blacklists.addAll(query.list());
-        });
-
-        return blacklists;
+        return read(session -> session
+            .createSelectionQuery("FROM OBlacklist o WHERE o.guild.guildId = :guildId ORDER BY o.id", OBlacklist.class)
+            .setParameter("guildId", guildId)
+            .getResultList());
     }
 
-    public void add(OGuild oGuild, Member member, String word) {
-        JpaUtils.runWithTransaction(session -> {
-            OBlacklist bl = getWordFromDb(oGuild.getGuildId(), word);
+    public Set<String> findEnabledWords(String guildId) {
+        return read(session -> session
+            .createSelectionQuery("SELECT o.word FROM OBlacklist o WHERE o.guild.guildId = :guildId AND o.enabled = true", String.class)
+            .setParameter("guildId", guildId)
+            .getResultStream()
+            .collect(Collectors.toUnmodifiableSet()));
+    }
 
-            if (bl == null) {
-                bl = new OBlacklist();
-                bl.setGuild(oGuild);
-                bl.setCreatorId(member.getId());
-                bl.setWord(word);
-                bl.setEnabled(true);
-
-                session.persist(bl);
-            } else {
-                bl.setEnabled(true);
-                session.merge(bl);
+    /**
+     * Adds the word to the guild's blacklist, or re-enables it if it already exists. Lookup and
+     * write happen in the same transaction.
+     *
+     * @param guildId   the guild id (the guild row must exist)
+     * @param creatorId the user adding the word
+     * @param word      the word
+     * @return what changed
+     */
+    public EnableOutcome enableWord(String guildId, String creatorId, String word) {
+        return write(session -> {
+            List<OBlacklist> existing = findWord(session, guildId, word);
+            if (existing.isEmpty()) {
+                OBlacklist blacklist = new OBlacklist();
+                blacklist.setGuild(session.getReference(OGuild.class, guildId));
+                blacklist.setCreatorId(creatorId);
+                blacklist.setWord(word);
+                blacklist.setEnabled(true);
+                session.persist(blacklist);
+                return EnableOutcome.CREATED;
             }
-        });
-    }
 
-    public void delete(OGuild oGuild, String word) {
-        JpaUtils.runWithTransaction(session -> {
-            OBlacklist bl = getWordFromDb(oGuild.getGuildId(), word);
-            if (bl != null) {
-                session.remove(bl);
+            boolean changed = false;
+            for (OBlacklist blacklist : existing) {
+                if (!Boolean.TRUE.equals(blacklist.getEnabled())) {
+                    blacklist.setEnabled(true);
+                    changed = true;
+                }
             }
+            return changed ? EnableOutcome.ENABLED : EnableOutcome.UNCHANGED;
         });
     }
 
-    private OBlacklist getWordFromDb(String guildId, String word) {
-        try (Session session = JpaUtils.openSession()) {
-            Query<OBlacklist> query = session.createQuery("SELECT o FROM OBlacklist o WHERE upper(o.word) = upper(:word) AND o.guild.guildId = :guildId", OBlacklist.class);
-            query.setParameter("guildId", guildId);
-            query.setParameter("word", word);
-            OBlacklist blacklist = query.uniqueResult();
+    /**
+     * Deletes the word (case-insensitive) from the guild's blacklist.
+     *
+     * @param guildId the guild id
+     * @param word    the word
+     * @return {@code true} if at least one row was deleted
+     */
+    public boolean deleteWord(String guildId, String word) {
+        return write(session -> {
+            List<OBlacklist> existing = findWord(session, guildId, word);
+            existing.forEach(session::remove);
+            return !existing.isEmpty();
+        });
+    }
 
-            session.close();
-            return blacklist;
-        }
+    private static List<OBlacklist> findWord(Session session, String guildId, String word) {
+        return session
+            .createSelectionQuery("FROM OBlacklist o WHERE upper(o.word) = upper(:word) AND o.guild.guildId = :guildId", OBlacklist.class)
+            .setParameter("guildId", guildId)
+            .setParameter("word", word)
+            .getResultList();
     }
 }

src/main/java/me/bobert/netneutrality/db/repository/GuildRepository.java

@@ -1,8 +1,4 @@
-package me.bobert.netneutrality.db.repository;/*
- * Copyright (c) anthorob
- *
- * https://discord.gg/qUa6zNFZsd
- */
+package me.bobert.netneutrality.db.repository;
 
 /*
  * Copyright (c) anthorob
@@ -10,49 +6,31 @@ package me.bobert.netneutrality.db.repository;/*
  * https://discord.gg/qUa6zNFZsd
  */
 
-import me.bobert.netneutrality.db.Repository;
+import me.bobert.netneutrality.db.AbstractRepository;
+import me.bobert.netneutrality.db.SessionProvider;
 import me.bobert.netneutrality.db.entities.OGuild;
-import me.bobert.netneutrality.db.JpaUtils;
-import org.hibernate.Session;
-import org.hibernate.query.Query;
 
-import java.util.ArrayList;
-import java.util.List;
+public class GuildRepository extends AbstractRepository<OGuild, String> {
 
-public class GuildRepository implements Repository<OGuild> {
-    @Override
-    public List<OGuild> findAll() {
-        List<OGuild> guilds = new ArrayList<>();
-
-        JpaUtils.runWithSession(session -> {
-            Query<OGuild> query = session.createQuery("FROM OGuild", OGuild.class);
-
-            guilds.addAll(query.list());
-        });
-
-        return guilds;
+    public GuildRepository(SessionProvider sessions) {
+        super(sessions, OGuild.class);
     }
 
-    @Override
-    public OGuild findById(String id) {
-        try (Session session = JpaUtils.openSession()) {
-            Query<OGuild> query = session.createQuery("SELECT o FROM OGuild o WHERE o.guildId = :guildId", OGuild.class);
-            query.setParameter("guildId", id);
-
-            return query.uniqueResult();
-        }
-    }
-
-    @Override
-    public void deleteBy(String id) {
-        JpaUtils.runWithTransaction(session -> {
-            Query<OGuild> query = session.createQuery("SELECT o FROM OGuild o WHERE o.guildId = :guildId", OGuild.class);
-            query.setParameter("guildId", id);
-
-            OGuild oGuild = query.uniqueResult();
-            if (oGuild != null) {
-                session.remove(oGuild);
+    /**
+     * Returns the guild row, inserting it first if it does not exist yet.
+     *
+     * @param guildId the Discord guild id
+     * @return the persistent guild
+     */
+    public OGuild findOrCreate(String guildId) {
+        return write(session -> {
+            OGuild guild = session.find(OGuild.class, guildId);
+            if (guild == null) {
+                guild = new OGuild();
+                guild.setGuildId(guildId);
+                session.persist(guild);
             }
+            return guild;
         });
     }
 }

src/main/java/me/bobert/netneutrality/db/repository/GuildSettingRepository.java

@@ -1,8 +1,4 @@
-package me.bobert.netneutrality.db.repository;/*
- * Copyright (c) anthorob
- *
- * https://discord.gg/qUa6zNFZsd
- */
+package me.bobert.netneutrality.db.repository;
 
 /*
  * Copyright (c) anthorob
@@ -10,88 +6,56 @@ package me.bobert.netneutrality.db.repository;/*
  * https://discord.gg/qUa6zNFZsd
  */
 
+import me.bobert.netneutrality.db.AbstractRepository;
 import me.bobert.netneutrality.db.GSettings;
-import me.bobert.netneutrality.db.Repository;
+import me.bobert.netneutrality.db.SessionProvider;
 import me.bobert.netneutrality.db.entities.OGuild;
 import me.bobert.netneutrality.db.entities.OGuildSetting;
-import me.bobert.netneutrality.db.JpaUtils;
-import org.hibernate.Session;
-import org.hibernate.query.Query;
 
-import java.util.ArrayList;
 import java.util.List;
 
-public class GuildSettingRepository implements Repository<OGuildSetting> {
-    @Override
-    public List<OGuildSetting> findAll() {
-        List<OGuildSetting> settings = new ArrayList<>();
+public class GuildSettingRepository extends AbstractRepository<OGuildSetting, Integer> {
 
-        JpaUtils.runWithSession(session -> {
-            Query<OGuildSetting> query = session.createQuery("FROM OGuildSetting", OGuildSetting.class);
-
-            settings.addAll(query.list());
-        });
-
-        return settings;
-    }
-
-    @Override
-    public OGuildSetting findById(String id) {
-        try (Session session = JpaUtils.openSession()) {
-            Query<OGuildSetting> query = session.createQuery("SELECT o FROM OGuildSetting o WHERE o.id = :id", OGuildSetting.class);
-            query.setParameter("id", id);
-
-            return query.uniqueResult();
-        }
-    }
-
-    @Override
-    public void deleteBy(String id) {
-        JpaUtils.runWithTransaction(session -> {
-            Query<OGuildSetting> query = session.createQuery("SELECT o FROM OGuildSetting o WHERE o.id = :id", OGuildSetting.class);
-            query.setParameter("id", id);
-
-            OGuildSetting setting = query.uniqueResult();
-            if (setting != null) {
-                session.remove(setting);
-            }
-        });
+    public GuildSettingRepository(SessionProvider sessions) {
+        super(sessions, OGuildSetting.class);
     }
 
     public List<OGuildSetting> findByGuild(String guildId) {
-        List<OGuildSetting> settings = new ArrayList<>();
-
-        JpaUtils.runWithSession(session -> {
-            Query<OGuildSetting> query = session.createQuery("SELECT o FROM OGuildSetting o WHERE o.guild.guildId = :guildId", OGuildSetting.class);
-            query.setParameter("guildId", guildId);
-
-            settings.addAll(query.list());
-        });
-
-        return settings;
+        return read(session -> session
+            .createSelectionQuery("FROM OGuildSetting o WHERE o.guild.guildId = :guildId", OGuildSetting.class)
+            .setParameter("guildId", guildId)
+            .getResultList());
     }
 
-    public void setSettingValue(OGuild oGuild, GSettings setting, String value) {
-        JpaUtils.getWithSession(oGuild, oGuild.getGuildId(), session -> {
-            OGuildSetting oGuildSetting = oGuild.getSettingByName(setting.getName());
+    /**
+     * Stores a non-default value, or deletes the row when the value is {@code null} or equal to the
+     * setting's default. Runs in a single transaction.
+     *
+     * @param guildId the guild id (the guild row must exist)
+     * @param setting the setting
+     * @param value   the new value, or {@code null} to reset
+     */
+    public void upsertOrDelete(String guildId, GSettings setting, String value) {
+        writeVoid(session -> {
+            List<OGuildSetting> existing = session
+                .createNamedSelectionQuery("settings_findByName", OGuildSetting.class)
+                .setParameter("id", guildId)
+                .setParameter("name", setting.getName())
+                .getResultList();
 
             if (value == null || setting.getDefaultValue().equals(value)) {
-                if (oGuildSetting != null) {
-                    session.remove(oGuildSetting);
-                }
+                existing.forEach(session::remove);
+                return;
+            }
+
+            if (existing.isEmpty()) {
+                OGuildSetting guildSetting = new OGuildSetting();
+                guildSetting.setGuild(session.getReference(OGuild.class, guildId));
+                guildSetting.setName(setting.getName());
+                guildSetting.setValue(value);
+                session.persist(guildSetting);
             } else {
-                if (oGuildSetting == null) {
-                    oGuildSetting = new OGuildSetting();
-                    oGuildSetting.setGuild(oGuild);
-                    oGuildSetting.setName(setting.getName());
-                    oGuildSetting.setValue(value);
-
-                    session.persist(oGuildSetting);
-                } else {
-                    oGuildSetting.setValue(value);
-
-                    session.merge(oGuildSetting);
-                }
+                existing.forEach(guildSetting -> guildSetting.setValue(value));
             }
         });
     }

src/main/java/me/bobert/netneutrality/db/repository/MessageRepository.java

@@ -1,105 +1,104 @@
 package me.bobert.netneutrality.db.repository;
+
 /*
  * Copyright (c) anthorob
  *
  * https://discord.gg/qUa6zNFZsd
  */
 
-import me.bobert.netneutrality.db.Repository;
+import me.bobert.netneutrality.db.AbstractRepository;
+import me.bobert.netneutrality.db.SessionProvider;
 import me.bobert.netneutrality.db.entities.OGuild;
 import me.bobert.netneutrality.db.entities.OLogMessage;
-import me.bobert.netneutrality.db.JpaUtils;
-import net.dv8tion.jda.api.entities.Member;
-import net.dv8tion.jda.api.entities.Message;
-import net.dv8tion.jda.api.entities.channel.middleman.MessageChannel;
 import org.hibernate.Session;
-import org.hibernate.query.Query;
 
-import java.util.ArrayList;
+import java.time.Instant;
 import java.util.List;
+import java.util.Optional;
 
-public class MessageRepository implements Repository<OLogMessage> {
-    @Override
-    public List<OLogMessage> findAll() {
-        List<OLogMessage> messages = new ArrayList<>();
+public class MessageRepository extends AbstractRepository<OLogMessage, Integer> {
 
-        JpaUtils.runWithSession(session -> {
-            Query<OLogMessage> query = session.createQuery("FROM OLogMessage", OLogMessage.class);
-
-            messages.addAll(query.list());
-        });
-
-        return messages;
+    public MessageRepository(SessionProvider sessions) {
+        super(sessions, OLogMessage.class);
     }
 
-    @Override
-    public OLogMessage findById(String id) {
-        try (Session session = JpaUtils.openSession()) {
-            Query<OLogMessage> query = session.createQuery("SELECT o FROM OLogMessage o WHERE o.messageId = :messageId", OLogMessage.class);
-            query.setParameter("messageId", id);
-
-            return query.uniqueResult();
-        }
-    }
-
-    @Override
-    public void deleteBy(String id) {
-        JpaUtils.runWithTransaction(session -> {
-            Query<OLogMessage> query = session.createQuery("SELECT o FROM OLogMessage o WHERE o.messageId = :messageId", OLogMessage.class);
-            query.setParameter("messageId", id);
-
-            OLogMessage oLogMessage = query.uniqueResult();
-            if (oLogMessage != null) {
-                session.remove(oLogMessage);
-            }
-        });
-    }
-
-    //TODO: move to a service
-    public void log(OGuild oGuild, MessageChannel channel, Member author, Message message) {
-        JpaUtils.runWithTransaction(session -> {
+    /**
+     * Stores a logged message.
+     *
+     * @param guildId   the guild id (the guild row must exist)
+     * @param channelId the channel id
+     * @param userId    the author id
+     * @param messageId the Discord message id
+     * @param content   the raw message content
+     * @param sentAt    when the message was sent
+     * @return the persistent log entry
+     */
+    public OLogMessage log(String guildId, String channelId, String userId, String messageId, String content, Instant sentAt) {
+        return write(session -> {
             OLogMessage logMessage = new OLogMessage();
-            logMessage.setGuild(oGuild);
-            logMessage.setMessageId(message.getId());
-            logMessage.setMessage(message.getContentRaw().trim());
-            logMessage.setChannelId(channel.getId());
-            logMessage.setUserId(author.getId());
-            logMessage.setDateSent(message.getTimeCreated().toInstant());
-
+            logMessage.setGuild(session.getReference(OGuild.class, guildId));
+            logMessage.setChannelId(channelId);
+            logMessage.setUserId(userId);
+            logMessage.setMessageId(messageId);
+            logMessage.setMessage(content == null ? null : content.trim());
+            logMessage.setDateSent(sentAt);
             session.persist(logMessage);
+            return logMessage;
         });
     }
 
-    public void logEdit(String messageId, String newMessage) {
-        JpaUtils.runWithTransaction(session -> {
-            Query<OLogMessage> query = session.createQuery("SELECT o FROM OLogMessage o WHERE o.messageId = :messageId", OLogMessage.class);
-            query.setParameter("messageId", messageId);
+    public Optional<OLogMessage> findByMessageId(String messageId) {
+        return read(session -> findByMessageId(session, messageId));
+    }
 
-            OLogMessage message = query.uniqueResult();
-            if (message != null) {
+    public Optional<String> findMessageContent(String messageId) {
+        return findByMessageId(messageId).map(OLogMessage::getMessage);
+    }
+
+    /**
+     * Records the edited content of a logged message.
+     *
+     * @param messageId  the Discord message id
+     * @param newMessage the edited content
+     * @return {@code true} if the message was found and updated
+     */
+    public boolean updateEditedMessage(String messageId, String newMessage) {
+        return write(session -> findByMessageId(session, messageId)
+            .map(message -> {
                 message.setEditedMessage(newMessage);
-
-                session.merge(message);
-            }
-        });
+                return true;
+            })
+            .orElse(false));
     }
 
-    public List<OLogMessage> getMessagesFromUser(String userId, String guildId, int max) {
-        List<OLogMessage> messages = new ArrayList<>();
-
-        JpaUtils.runWithSession(session -> {
-            Query<OLogMessage> query = session.createQuery("SELECT o FROM OLogMessage o WHERE o.guild.guildId = :guildId AND o.userId = :userId", OLogMessage.class);
-            query.setParameter("guildId", guildId);
-            query.setParameter("userId", userId);
-            query.setMaxResults(max);
-
-            messages.addAll(query.list());
-        });
-
-        return messages;
+    public boolean deleteByMessageId(String messageId) {
+        return write(session -> session
+            .createMutationQuery("DELETE FROM OLogMessage o WHERE o.messageId = :messageId")
+            .setParameter("messageId", messageId)
+            .executeUpdate() > 0);
     }
 
-    public String getMessageString(String messageId) {
-        return findById(messageId).getMessage();
+    /**
+     * Returns the most recent messages of a user in a guild, newest first.
+     *
+     * @param userId  the user id
+     * @param guildId the guild id
+     * @param max     the maximum number of messages
+     * @return the messages
+     */
+    public List<OLogMessage> findByUser(String userId, String guildId, int max) {
+        return read(session -> session
+            .createSelectionQuery("FROM OLogMessage o WHERE o.guild.guildId = :guildId AND o.userId = :userId ORDER BY o.dateSent DESC", OLogMessage.class)
+            .setParameter("guildId", guildId)
+            .setParameter("userId", userId)
+            .setMaxResults(max)
+            .getResultList());
+    }
+
+    private static Optional<OLogMessage> findByMessageId(Session session, String messageId) {
+        return session
+            .createSelectionQuery("FROM OLogMessage o WHERE o.messageId = :messageId", OLogMessage.class)
+            .setParameter("messageId", messageId)
+            .uniqueResultOptional();
     }
 }

src/main/java/me/bobert/netneutrality/db/repository/TaskRepository.java

@@ -1,55 +1,63 @@
 package me.bobert.netneutrality.db.repository;
+
 /*
  * Copyright (c) anthorob
  *
  * https://discord.gg/qUa6zNFZsd
  */
 
-
-import me.bobert.netneutrality.db.Repository;
+import me.bobert.netneutrality.db.AbstractRepository;
+import me.bobert.netneutrality.db.SessionProvider;
 import me.bobert.netneutrality.db.entities.OTask;
-import me.bobert.netneutrality.db.JpaUtils;
 import org.hibernate.Session;
-import org.hibernate.query.Query;
 
-import java.util.ArrayList;
-import java.util.List;
+import java.util.Optional;
 
-public class TaskRepository implements Repository<OTask> {
+public class TaskRepository extends AbstractRepository<OTask, Integer> {
 
-    @Override
-    public List<OTask> findAll() {
-        List<OTask> tasks = new ArrayList<>();
-
-        JpaUtils.runWithSession(session -> {
-            Query<OTask> query = session.createQuery("FROM OTask", OTask.class);
-
-            tasks.addAll(query.list());
-        });
-
-        return tasks;
+    public TaskRepository(SessionProvider sessions) {
+        super(sessions, OTask.class);
     }
 
-    @Override
-    public OTask findById(String id) {
-        try (Session session = JpaUtils.openSession()) {
-            Query<OTask> query = session.createQuery("SELECT o FROM OTask o WHERE o.taskId = :taskId", OTask.class);
-            query.setParameter("taskId", id);
-
-            return query.uniqueResult();
-        }
+    public Optional<OTask> findByTaskId(String taskId) {
+        return read(session -> findByTaskId(session, taskId));
     }
 
-    @Override
-    public void deleteBy(String id) {
-        JpaUtils.runWithTransaction(session -> {
-            Query<OTask> query = session.createQuery("SELECT o FROM OTask o WHERE o.taskId = :taskId", OTask.class);
-            query.setParameter("taskId", id);
-
-            OTask oTask = query.uniqueResult();
-            if (oTask != null) {
-                session.remove(oTask);
+    /**
+     * Inserts the task or updates its payload, in a single transaction.
+     *
+     * @param taskId  the logical task id
+     * @param typeId  the persistable task type id
+     * @param payload the serialized payload
+     * @return the persistent task
+     */
+    public OTask upsert(String taskId, String typeId, String payload) {
+        return write(session -> {
+            OTask task = findByTaskId(session, taskId).orElse(null);
+            if (task == null) {
+                task = new OTask();
+                task.setTaskId(taskId);
+                task.setTaskClass(typeId);
+                task.setPayload(payload);
+                session.persist(task);
+            } else {
+                task.setPayload(payload);
             }
+            return task;
         });
     }
+
+    public boolean deleteByTaskId(String taskId) {
+        return write(session -> session
+            .createMutationQuery("DELETE FROM OTask o WHERE o.taskId = :taskId")
+            .setParameter("taskId", taskId)
+            .executeUpdate() > 0);
+    }
+
+    private static Optional<OTask> findByTaskId(Session session, String taskId) {
+        return session
+            .createSelectionQuery("FROM OTask o WHERE o.taskId = :taskId", OTask.class)
+            .setParameter("taskId", taskId)
+            .uniqueResultOptional();
+    }
 }

src/main/java/me/bobert/netneutrality/db/service/BlacklistEntry.java

@@ -0,0 +1,16 @@
+package me.bobert.netneutrality.db.service;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+/**
+ * Read-only view of a blacklisted word.
+ *
+ * @param word    the word
+ * @param enabled whether the word is currently enforced
+ */
+public record BlacklistEntry(String word, boolean enabled) {
+}

src/main/java/me/bobert/netneutrality/db/service/BlacklistResult.java

@@ -0,0 +1,23 @@
+package me.bobert.netneutrality.db.service;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+/**
+ * Outcome of a blacklist change made through {@link BlacklistService}.
+ */
+public enum BlacklistResult {
+    /** The word was added to the blacklist. */
+    ADDED,
+    /** The word existed but was disabled, and is now enabled again. */
+    REENABLED,
+    /** The word was already blacklisted; nothing changed. */
+    ALREADY_EXISTS,
+    /** The word was removed from the blacklist. */
+    REMOVED,
+    /** The word was not blacklisted; nothing changed. */
+    NOT_FOUND
+}

src/main/java/me/bobert/netneutrality/db/service/BlacklistService.java

@@ -6,93 +6,108 @@ package me.bobert.netneutrality.db.service;
  * https://discord.gg/qUa6zNFZsd
  */
 
-import me.bobert.netneutrality.core.command.CommandExecutionResult;
-import me.bobert.netneutrality.db.entities.OBlacklist;
-import me.bobert.netneutrality.db.entities.OGuild;
 import me.bobert.netneutrality.db.repository.BlacklistRepository;
-import me.bobert.netneutrality.db.JpaUtils;
-import net.dv8tion.jda.api.entities.Member;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 
-import java.util.Collections;
 import java.util.List;
-import java.util.Map;
+import java.util.Locale;
+import java.util.Objects;
 import java.util.Set;
-import java.util.concurrent.ConcurrentHashMap;
+import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
+/**
+ * Per-guild blacklist, backed by the {@code blacklist} table and an in-memory cache of the enabled
+ * words. Persistence failures propagate to the caller.
+ */
 public class BlacklistService {
-    private static final Logger logger = LoggerFactory.getLogger(BlacklistService.class);
-    private static final Map<String, Set<String>> blacklistCache = new ConcurrentHashMap<>();
+    private static final Logger logger = LogManager.getLogger(BlacklistService.class);
+    private static final Pattern WORD_SEPARATOR = Pattern.compile("[^\\p{L}\\p{N}]+");
+
     private final BlacklistRepository blacklistRepository;
     private final GuildService guildService;
+    private volatile Set<String> enabledWords = Set.of();
 
-    public BlacklistService(GuildService guildService) {
-        this.blacklistRepository = new BlacklistRepository();
-        this.guildService = guildService;
-        init();
-    }
-
-    private void init() {
+    public BlacklistService(GuildService guildService, BlacklistRepository blacklistRepository) {
+        this.guildService = Objects.requireNonNull(guildService, "guildService");
+        this.blacklistRepository = Objects.requireNonNull(blacklistRepository, "blacklistRepository");
         reloadBlacklistCache();
     }
 
     public void reloadBlacklistCache() {
-        OGuild oGuild = guildService.getEntity();
-        logger.debug("Reloading blacklist cache for guild: {}", oGuild.getGuildId());
-
-        JpaUtils.getWithSession(oGuild, oGuild.getGuildId(), session -> {
-            Set<String> blacklistWords = oGuild.getBlacklists().stream()
-                .filter(OBlacklist::getEnabled)
-                .map(OBlacklist::getWord)
-                .collect(Collectors.toSet());
-
-            blacklistCache.put(oGuild.getGuildId(), blacklistWords);
-        });
+        logger.debug("Reloading blacklist cache for guild: {}", guildService.getGuildId());
+        enabledWords = blacklistRepository.findEnabledWords(guildService.getGuildId()).stream()
+            .map(BlacklistService::normalize)
+            .collect(Collectors.toUnmodifiableSet());
     }
 
-    public CommandExecutionResult add(Member member, String word) {
-        try {
-            blacklistRepository.add(guildService.getEntity(), member, word);
-            reloadBlacklistCache();
+    /**
+     * Adds the word to the blacklist, or re-enables it.
+     *
+     * @param creatorUserId the id of the user adding the word
+     * @param word          the word
+     * @return {@link BlacklistResult#ADDED}, {@link BlacklistResult#REENABLED} or
+     *     {@link BlacklistResult#ALREADY_EXISTS}
+     */
+    public BlacklistResult add(String creatorUserId, String word) {
+        guildService.ensureEntity();
+        BlacklistRepository.EnableOutcome outcome =
+            blacklistRepository.enableWord(guildService.getGuildId(), creatorUserId, word);
+        reloadBlacklistCache();
 
-            return CommandExecutionResult.success("Added the word [%s] to the blacklist.", word);
-        } catch (Exception e) {
-            return CommandExecutionResult.warn("Failed to add word to blacklist: " + e.getMessage());
-        }
+        return switch (outcome) {
+            case CREATED -> BlacklistResult.ADDED;
+            case ENABLED -> BlacklistResult.REENABLED;
+            case UNCHANGED -> BlacklistResult.ALREADY_EXISTS;
+        };
     }
 
-    public CommandExecutionResult delete(String word) {
-        try {
-            blacklistRepository.delete(guildService.getEntity(), word);
-            reloadBlacklistCache();
+    /**
+     * Removes the word from the blacklist.
+     *
+     * @param word the word
+     * @return {@link BlacklistResult#REMOVED} or {@link BlacklistResult#NOT_FOUND}
+     */
+    public BlacklistResult remove(String word) {
+        boolean deleted = blacklistRepository.deleteWord(guildService.getGuildId(), word);
+        reloadBlacklistCache();
 
-            return CommandExecutionResult.success("Removed the word [%s] to the blacklist.", word);
-        } catch (Exception e) {
-            return CommandExecutionResult.warn("Failed to remove word from blacklist: " + e.getMessage());
-        }
+        return deleted ? BlacklistResult.REMOVED : BlacklistResult.NOT_FOUND;
     }
 
-    public List<OBlacklist> getBlacklistForGuild() {
-        try {
-            return blacklistRepository.findByGuildId(guildService.getEntity().getGuildId());
-        } catch (Exception e) {
-            return List.of();
+    public List<BlacklistEntry> list() {
+        return blacklistRepository.findByGuildId(guildService.getGuildId()).stream()
+            .map(blacklist -> new BlacklistEntry(blacklist.getWord(), Boolean.TRUE.equals(blacklist.getEnabled())))
+            .toList();
+    }
+
+    /**
+     * Returns whether any word of the text is an enabled blacklisted word (case-insensitive).
+     *
+     * @param text the text to check
+     * @return {@code true} if the text contains a blacklisted word
+     */
+    public boolean containsBlacklistedWord(String text) {
+        Set<String> words = enabledWords;
+        if (text == null || words.isEmpty()) {
+            return false;
         }
+
+        for (String token : WORD_SEPARATOR.split(text)) {
+            if (!token.isEmpty() && words.contains(normalize(token))) {
+                return true;
+            }
+        }
+        return false;
     }
 
     public void removeGuildBlacklist() {
-        logger.info("Clearing blacklist cache for guild: {}", guildService.getEntity().getGuildId());
-        blacklistCache.remove(guildService.getEntity().getGuildId());
+        logger.info("Clearing blacklist cache for guild: {}", guildService.getGuildId());
+        enabledWords = Set.of();
     }
 
-    public static boolean isWordBlacklisted(String guildId, String word) {
-        Set<String> blacklistWords = blacklistCache.get(guildId);
-        return blacklistWords != null && blacklistWords.contains(word);
-    }
-
-    public static Set<String> getBlacklist(String guildId) {
-        return blacklistCache.getOrDefault(guildId, Collections.emptySet());
+    private static String normalize(String word) {
+        return word.toLowerCase(Locale.ROOT);
     }
 }

src/main/java/me/bobert/netneutrality/db/service/GuildService.java

@@ -7,10 +7,13 @@ package me.bobert.netneutrality.db.service;
  */
 
 import me.bobert.netneutrality.db.entities.OGuild;
+import me.bobert.netneutrality.db.repository.BlacklistRepository;
 import me.bobert.netneutrality.db.repository.GuildRepository;
-import me.bobert.netneutrality.db.JpaUtils;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+import me.bobert.netneutrality.db.repository.GuildSettingRepository;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.util.Objects;
 
 /**
  * Per-guild domain service (blacklist, settings, entity access).
@@ -19,16 +22,24 @@ import org.slf4j.LoggerFactory;
  * {@link me.bobert.netneutrality.db.service.GuildServiceProvider}.
  */
 public class GuildService {
-    private static final Logger logger = LoggerFactory.getLogger(GuildService.class);
-    private final GuildRepository guildRepository = new GuildRepository();
+    private static final Logger logger = LogManager.getLogger(GuildService.class);
+    private final String guildId;
+    private final GuildRepository guildRepository;
     private final BlacklistService blacklistService;
     private final GuildSettingService guildSettingService;
-    private OGuild oGuild;
+    private volatile OGuild oGuild;
 
-    GuildService(String guildId) {
+    public GuildService(String guildId, GuildRepository guildRepository, BlacklistRepository blacklistRepository,
+                        GuildSettingRepository guildSettingRepository) {
+        this.guildId = Objects.requireNonNull(guildId, "guildId");
+        this.guildRepository = Objects.requireNonNull(guildRepository, "guildRepository");
         this.oGuild = findOrCreateGuild(guildId);
-        this.blacklistService = new BlacklistService(this);
-        this.guildSettingService = new GuildSettingService(this);
+        this.blacklistService = new BlacklistService(this, blacklistRepository);
+        this.guildSettingService = new GuildSettingService(this, guildSettingRepository);
+    }
+
+    public String getGuildId() {
+        return guildId;
     }
 
     public OGuild getEntity() {
@@ -43,17 +54,23 @@ public class GuildService {
         return guildSettingService;
     }
 
+    /**
+     * Returns the guild row, creating it when it does not exist (for example after it was deleted
+     * while the service was cached).
+     *
+     * @param guildId the guild id
+     * @return the persistent guild
+     */
     public OGuild findOrCreateGuild(String guildId) {
-        OGuild guildEntity = guildRepository.findById(guildId);
-        if (guildEntity == null) {
-            logger.debug("Guild[{}] doesn't exist in DB, creating entity..", guildId);
+        logger.debug("Loading Guild[{}]", guildId);
+        return guildRepository.findOrCreate(guildId);
+    }
 
-            guildEntity = new OGuild();
-            guildEntity.setGuildId(guildId);
-            guildRepository.save(guildEntity);
-        }
-
-        return guildEntity;
+    /**
+     * Makes sure the guild row exists before writing rows that reference it.
+     */
+    void ensureEntity() {
+        this.oGuild = findOrCreateGuild(guildId);
     }
 
     public boolean isDebugEnabled() {
@@ -61,14 +78,17 @@ public class GuildService {
     }
 
     public void updateDebugMode(boolean debug) {
-        JpaUtils.updateWithTransaction(oGuild, () -> oGuild.setDebug(debug));
+        OGuild current = findOrCreateGuild(guildId);
+        current.setDebug(debug);
+        this.oGuild = guildRepository.save(current);
     }
 
     public void deleteGuild() {
-        guildRepository.deleteBy(oGuild.getGuildId());
+        guildRepository.deleteById(guildId);
+        blacklistService.removeGuildBlacklist();
     }
 
     public void reloadEntity() {
-        this.oGuild = findOrCreateGuild(oGuild.getGuildId());
+        ensureEntity();
     }
 }

src/main/java/me/bobert/netneutrality/db/service/GuildServiceProvider.java

@@ -6,8 +6,6 @@ package me.bobert.netneutrality.db.service;
  * https://discord.gg/qUa6zNFZsd
  */
 
-import net.dv8tion.jda.api.entities.Guild;
-
 import java.util.Map;
 
 /**
@@ -24,17 +22,16 @@ public interface GuildServiceProvider {
     GuildService get(String guildId);
 
     /**
-     * Returns (creating on first use) the service for the given guild.
+     * Drops the cached service for the guild; the next {@link #get(String)} builds a new one.
      *
-     * @param guild the Discord guild
-     * @return the guild service
+     * @param guildId the Discord guild id
      */
-    GuildService get(Guild guild);
+    void evict(String guildId);
 
     /**
-     * Returns the live cache of guild services.
+     * Returns a read-only snapshot of the cached guild services.
      *
      * @return the services keyed by guild id
      */
-    Map<String, GuildService> getServices();
+    Map<String, GuildService> snapshot();
 }

src/main/java/me/bobert/netneutrality/db/service/GuildServiceProviderImpl.java

@@ -6,9 +6,12 @@ package me.bobert.netneutrality.db.service;
  * https://discord.gg/qUa6zNFZsd
  */
 
-import net.dv8tion.jda.api.entities.Guild;
+import me.bobert.netneutrality.db.repository.BlacklistRepository;
+import me.bobert.netneutrality.db.repository.GuildRepository;
+import me.bobert.netneutrality.db.repository.GuildSettingRepository;
 
 import java.util.Map;
+import java.util.Objects;
 import java.util.concurrent.ConcurrentHashMap;
 
 /**
@@ -17,22 +20,30 @@ import java.util.concurrent.ConcurrentHashMap;
 public class GuildServiceProviderImpl implements GuildServiceProvider {
 
     private final Map<String, GuildService> services = new ConcurrentHashMap<>();
+    private final GuildRepository guildRepository;
+    private final BlacklistRepository blacklistRepository;
+    private final GuildSettingRepository guildSettingRepository;
 
-    public GuildServiceProviderImpl() {
+    public GuildServiceProviderImpl(GuildRepository guildRepository, BlacklistRepository blacklistRepository,
+                                    GuildSettingRepository guildSettingRepository) {
+        this.guildRepository = Objects.requireNonNull(guildRepository, "guildRepository");
+        this.blacklistRepository = Objects.requireNonNull(blacklistRepository, "blacklistRepository");
+        this.guildSettingRepository = Objects.requireNonNull(guildSettingRepository, "guildSettingRepository");
     }
 
     @Override
     public GuildService get(String guildId) {
-        return services.computeIfAbsent(guildId, GuildService::new);
+        return services.computeIfAbsent(guildId,
+            id -> new GuildService(id, guildRepository, blacklistRepository, guildSettingRepository));
     }
 
     @Override
-    public GuildService get(Guild guild) {
-        return get(guild.getId());
+    public void evict(String guildId) {
+        services.remove(guildId);
     }
 
     @Override
-    public Map<String, GuildService> getServices() {
-        return services;
+    public Map<String, GuildService> snapshot() {
+        return Map.copyOf(services);
     }
 }

src/main/java/me/bobert/netneutrality/db/service/GuildSettingService.java

@@ -9,52 +9,73 @@ package me.bobert.netneutrality.db.service;
 import me.bobert.netneutrality.db.GSettings;
 import me.bobert.netneutrality.db.entities.OGuildSetting;
 import me.bobert.netneutrality.db.repository.GuildSettingRepository;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 
-import java.util.List;
+import java.util.HashMap;
 import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
+import java.util.Objects;
+import java.util.Optional;
 
+/**
+ * Per-guild settings, backed by the {@code guild_settings} table. Only non-default values are
+ * stored; reads come from an immutable snapshot that is swapped atomically on reload.
+ */
 public class GuildSettingService {
-    private static final Logger logger = LoggerFactory.getLogger(GuildSettingService.class);
-    private final GuildSettingRepository guildSettingRepository = new GuildSettingRepository();
+    private static final Logger logger = LogManager.getLogger(GuildSettingService.class);
+    private final GuildSettingRepository guildSettingRepository;
     private final GuildService guildService;
-    private final Map<String, String> settingsCache = new ConcurrentHashMap<>();
+    private volatile Map<String, String> settingsCache = Map.of();
 
-    public GuildSettingService(GuildService guildService) {
-        this.guildService = guildService;
+    public GuildSettingService(GuildService guildService, GuildSettingRepository guildSettingRepository) {
+        this.guildService = Objects.requireNonNull(guildService, "guildService");
+        this.guildSettingRepository = Objects.requireNonNull(guildSettingRepository, "guildSettingRepository");
         reloadSettingsCache();
     }
 
-    public Map<String, String> getSettings() {
+    /**
+     * @return an unmodifiable snapshot of the stored (non-default) settings, keyed by setting name
+     */
+    public Map<String, String> snapshot() {
         return settingsCache;
     }
 
-    public String getSetting(GSettings setting) {
-        String value = settingsCache.get(setting.getName());
-
-        if (value == null) {
-            value = setting.getDefaultValue();
-        }
-
-        return value;
+    /**
+     * @param key the setting
+     * @return the stored value, or empty when the setting uses its default
+     */
+    public Optional<String> get(GSettings key) {
+        return Optional.ofNullable(settingsCache.get(key.getName()));
     }
 
-    public void setSettingValue(GSettings setting, String value) {
-        guildSettingRepository.setSettingValue(guildService.getEntity(), setting, value);
+    /**
+     * @param key the setting
+     * @return the stored value, or the setting's default
+     */
+    public String getOrDefault(GSettings key) {
+        return get(key).orElse(key.getDefaultValue());
+    }
+
+    /**
+     * Stores the value; {@code null} or the default value deletes the stored setting.
+     *
+     * @param key   the setting
+     * @param value the new value, or {@code null} to reset it
+     */
+    public void set(GSettings key, String value) {
+        guildService.ensureEntity();
+        guildSettingRepository.upsertOrDelete(guildService.getGuildId(), key, value);
 
         reloadSettingsCache();
     }
 
     public void reloadSettingsCache() {
-        logger.debug("Reloading settings cache for guild: {}", guildService.getEntity().getGuildId());
-        settingsCache.clear();
+        logger.debug("Reloading settings cache for guild: {}", guildService.getGuildId());
 
-
-        List<OGuildSetting> settings = guildSettingRepository.findByGuild(guildService.getEntity().getGuildId());
-        for (OGuildSetting setting : settings) {
-            settingsCache.put(setting.getName(), setting.getValue());
+        Map<String, String> fresh = new HashMap<>();
+        for (OGuildSetting setting : guildSettingRepository.findByGuild(guildService.getGuildId())) {
+            fresh.put(setting.getName(), setting.getValue());
         }
+        settingsCache = Map.copyOf(fresh);
     }
 }

src/main/java/me/bobert/netneutrality/db/service/TaskService.java

@@ -24,10 +24,10 @@ public class TaskService {
     private final TaskRepository taskRepository;
     private final PersistableTaskRegistry registry;
 
-    public TaskService(TaskManager taskManager, PersistableTaskRegistry registry) {
-        this.taskManager = taskManager;
-        this.taskRepository = new TaskRepository();
-        this.registry = registry;
+    public TaskService(TaskManager taskManager, PersistableTaskRegistry registry, TaskRepository taskRepository) {
+        this.taskManager = Objects.requireNonNull(taskManager, "taskManager");
+        this.registry = Objects.requireNonNull(registry, "registry");
+        this.taskRepository = Objects.requireNonNull(taskRepository, "taskRepository");
     }
 
     public void loadTasks() {
@@ -40,13 +40,11 @@ public class TaskService {
             String typeId = oTask.getTaskClass();
             logger.debug("Trying to load task with ID: {} and type: {}", taskId, typeId);
 
-            String payload = oTask.getPayload();
-
             try {
-                ObjectNode json = Json.readObject(payload);
+                ObjectNode json = Json.readObject(oTask.getPayload());
                 PersistableTask task = registry.create(typeId, json);
 
-                validateTask(task, oTask);
+                validateTask(task, taskId, json);
                 taskManager.insertPersistableTask(task);
             } catch (Exception e) {
                 logger.error("Error loading task with ID {}: {}", taskId, e.getMessage());
@@ -54,15 +52,11 @@ public class TaskService {
         }
     }
 
-    private void validateTask(PersistableTask task, OTask oTask) throws IllegalArgumentException {
-        String taskId = oTask.getTaskId();
-        String payload = oTask.getPayload();
-
+    private static void validateTask(PersistableTask task, String taskId, ObjectNode json) throws IllegalArgumentException {
         if (!Objects.equals(taskId, task.getId())) {
             throw new IllegalArgumentException("Task ID mismatch, expected: " + task.getId());
         }
 
-        ObjectNode json = Json.readObject(payload);
         String payloadId = json.path("id").asText(null);
         if (!Objects.equals(payloadId, task.getId())) {
             throw new IllegalArgumentException("Task payload ID mismatch, expected: " + task.getId());
@@ -81,24 +75,12 @@ public class TaskService {
             return;
         }
 
-        TaskRepository taskRepository = new TaskRepository();
-        OTask oTask = taskRepository.findById(task.getId());
-        if (oTask == null) {
-            oTask = new OTask();
-            oTask.setTaskId(task.getId());
-            oTask.setTaskClass(typeId);
-        }
-
-        oTask.setPayload(task.toPayload());
-
-        logger.info("Persisting task: {}", oTask.getTaskId());
-        taskRepository.save(oTask);
+        logger.info("Persisting task: {}", task.getId());
+        taskRepository.upsert(task.getId(), typeId, task.toPayload());
     }
 
     public void unpersistTask(PersistableTask task) {
         logger.debug("Unpersisting task: {}", task.getId());
-        TaskRepository taskRepository = new TaskRepository();
-
-        taskRepository.deleteBy(task.getId());
+        taskRepository.deleteByTaskId(task.getId());
     }
 }

src/main/java/me/bobert/netneutrality/hooks/EventsHandler.java

@@ -95,13 +95,29 @@ public class EventsHandler implements EventListener {
         addListener(ButtonInteractionEvent.class, ButtonTaskContext::new);
         addListener(MessageReactionAddEvent.class, EmojiTaskContext::new);
         addGenericListener(GuildJoinEvent.class, event -> {
-            GuildService service = guildServices.get(event.getGuild());
+            GuildService service = guildServices.get(event.getGuild().getId());
 
             if (service.isDebugEnabled()) {
                 LogHandler.sendMessageToDebugChannel(event.getGuild(), "Error logging enabled on this channel");
             }
         });
-        addGenericListener(GuildLeaveEvent.class, event -> guildServices.get(event.getGuild()).deleteGuild());
+        addGenericListener(GuildLeaveEvent.class, event -> onGuildLeave(event.getGuild().getId()));
+    }
+
+    /**
+     * Deletes the guild's data and drops its cached service. The service is evicted even when the
+     * delete fails, so a stale cache entry never outlives the guild membership.
+     *
+     * @param guildId the id of the guild the bot left
+     */
+    void onGuildLeave(String guildId) {
+        try {
+            guildServices.get(guildId).deleteGuild();
+        } catch (RuntimeException e) {
+            logger.error("Failed to delete data of guild {}", guildId, e);
+        } finally {
+            guildServices.evict(guildId);
+        }
     }
 
     /**

src/main/java/me/bobert/netneutrality/http/server/ActionRoutes.java

@@ -52,14 +52,14 @@ public final class ActionRoutes {
 
         routes.get("/actions/settings/current/{guildId}", ctx -> {
             Guild guild = GuildRoutes.guild(jdaSupplier, ctx);
-            Map<String, String> settings = guildServices.get(guild).getGuildSettingService().getSettings();
+            Map<String, String> settings = guildServices.get(guild.getId()).getGuildSettingService().snapshot();
 
             ctx.json(Map.of("status", "ok", "settings", settings));
         });
 
         routes.post("/actions/settings/reload/{guildId}", ctx -> {
             Guild guild = GuildRoutes.guild(jdaSupplier, ctx);
-            guildServices.get(guild).getGuildSettingService().reloadSettingsCache();
+            guildServices.get(guild.getId()).getGuildSettingService().reloadSettingsCache();
 
             ctx.json(Map.of("status", "true"));
         });

src/main/java/me/bobert/netneutrality/music/MusicManager.java

@@ -259,7 +259,7 @@ public class MusicManager implements MusicManagerCallback {
 
     private static int parseBaseVolume(GuildService guildService) {
         try {
-            return Integer.parseInt(guildService.getGuildSettingService().getSetting(GSettings.MUSIC_VOLUME));
+            return Integer.parseInt(guildService.getGuildSettingService().getOrDefault(GSettings.MUSIC_VOLUME));
         } catch (NumberFormatException e) {
             logger.warn("Invalid MUSIC_VOLUME setting, falling back to default ({})", DEFAULT_VOLUME, e);
             return DEFAULT_VOLUME;

src/main/java/me/bobert/netneutrality/music/MusicServiceImpl.java

@@ -105,7 +105,7 @@ public class MusicServiceImpl implements MusicService {
     public MusicManager get(Guild guild) {
         return managers.computeIfAbsent(
             guild.getId(),
-            id -> new MusicManager(guild, client, guildServices.get(guild), taskManager)
+            id -> new MusicManager(guild, client, guildServices.get(id), taskManager)
         );
     }
 

src/main/java/me/bobert/netneutrality/tasks/music/LoadPlaylistTask.java

@@ -63,7 +63,7 @@ public class LoadPlaylistTask extends ButtonTask implements WithChildren, Deleta
         int searchResultsLimit = 5; // Max number of buttons per row
         int maxPlaylistSizeBeforeAsking = Integer.parseInt(musicManager.getGuildService()
             .getGuildSettingService()
-            .getSetting(GSettings.MUSIC_MAXPLAYLISTSIZE));
+            .getOrDefault(GSettings.MUSIC_MAXPLAYLISTSIZE));
 
         // Search results
         if (searchResult) {

src/main/resources/hibernate.cfg.xml

@@ -7,6 +7,8 @@
         <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
         <property name="hibernate.connection.driver_class">com.mysql.cj.jdbc.Driver</property>
         <property name="hibernate.connection.provider_class">org.hibernate.hikaricp.internal.HikariCPConnectionProvider</property>
+        <!-- The schema is owned by Flyway; Hibernate only checks that the entities match it. -->
+        <property name="hibernate.hbm2ddl.auto">validate</property>
 
         <mapping class="me.bobert.netneutrality.db.entities.OBlacklist"/>
         <mapping class="me.bobert.netneutrality.db.entities.OGuild"/>
@@ -15,6 +17,7 @@
         <mapping class="me.bobert.netneutrality.db.entities.OLoggingId"/>
         <mapping class="me.bobert.netneutrality.db.entities.OLogMessage"/>
         <mapping class="me.bobert.netneutrality.db.entities.OTask"/>
+        <mapping class="me.bobert.netneutrality.db.entities.OWebUser"/>
 
     </session-factory>
 </hibernate-configuration>

src/test/java/me/bobert/netneutrality/command/admin/BlacklistCommandTest.java

@@ -0,0 +1,100 @@
+package me.bobert.netneutrality.command.admin;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import me.bobert.netneutrality.core.command.CommandExecutionResult;
+import me.bobert.netneutrality.core.command.CommandExecutionResult.Result;
+import me.bobert.netneutrality.core.context.CommandContext;
+import me.bobert.netneutrality.db.service.BlacklistResult;
+import me.bobert.netneutrality.db.service.BlacklistService;
+import me.bobert.netneutrality.db.service.GuildService;
+import me.bobert.netneutrality.db.service.GuildServiceProvider;
+import net.dv8tion.jda.api.entities.Guild;
+import net.dv8tion.jda.api.entities.Member;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+import java.util.function.Function;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+class BlacklistCommandTest {
+
+    private BlacklistService blacklist;
+    private CommandContext context;
+    private BlacklistCommand command;
+
+    @BeforeEach
+    void setUp() {
+        blacklist = mock(BlacklistService.class);
+        GuildService guildService = mock(GuildService.class);
+        when(guildService.getBlacklistService()).thenReturn(blacklist);
+        GuildServiceProvider provider = mock(GuildServiceProvider.class);
+        when(provider.get("guild-1")).thenReturn(guildService);
+
+        Guild guild = mock(Guild.class);
+        when(guild.getId()).thenReturn("guild-1");
+        Member member = mock(Member.class);
+        when(member.getId()).thenReturn("user-1");
+
+        context = mock(CommandContext.class);
+        when(context.getGuild()).thenReturn(guild);
+        when(context.getGuildUser()).thenReturn(member);
+        when(context.getOption(eq("word"), eq(""), any(Function.class))).thenReturn("foo");
+
+        command = new BlacklistCommand(provider);
+    }
+
+    @ParameterizedTest
+    @CsvSource({
+        "ADDED, SUCCESS",
+        "REENABLED, SUCCESS",
+        "ALREADY_EXISTS, WARN",
+        "REMOVED, SUCCESS",
+        "NOT_FOUND, WARN"
+    })
+    void mapsEveryResult(BlacklistResult result, Result expected) {
+        CommandExecutionResult reply = BlacklistCommand.toReply(result, "foo");
+
+        assertEquals(expected, reply.getResult());
+        assertTrue(reply.getMessage().contains("[foo]"));
+    }
+
+    @Test
+    void addPassesPlainIds() {
+        when(context.getSubcommand()).thenReturn("add");
+        when(blacklist.add("user-1", "foo")).thenReturn(BlacklistResult.ADDED);
+
+        assertEquals(Result.SUCCESS, command.execute(context).getResult());
+    }
+
+    @Test
+    void removeNotFoundWarns() {
+        when(context.getSubcommand()).thenReturn("remove");
+        when(blacklist.remove("foo")).thenReturn(BlacklistResult.NOT_FOUND);
+
+        assertEquals(Result.WARN, command.execute(context).getResult());
+    }
+
+    @Test
+    void persistenceFailureBecomesWarning() {
+        when(context.getSubcommand()).thenReturn("add");
+        when(blacklist.add("user-1", "foo")).thenThrow(new IllegalStateException("db down"));
+
+        CommandExecutionResult reply = command.execute(context);
+
+        assertEquals(Result.WARN, reply.getResult());
+        assertTrue(reply.getMessage().contains("db down"));
+    }
+}

src/test/java/me/bobert/netneutrality/core/tasks/TaskManagerImplTest.java

@@ -16,6 +16,7 @@ import me.bobert.netneutrality.core.tasks.trait.Deletable;
 import me.bobert.netneutrality.core.tasks.trait.WithButton;
 import me.bobert.netneutrality.core.tasks.trait.WithChildren;
 import me.bobert.netneutrality.core.tasks.trait.WithParent;
+import me.bobert.netneutrality.db.repository.TaskRepository;
 import me.bobert.netneutrality.db.service.TaskService;
 import me.bobert.netneutrality.scheduled.cleanup.TaskCleanup;
 import net.dv8tion.jda.api.components.buttons.Button;
@@ -61,7 +62,7 @@ class TaskManagerImplTest {
 
     @BeforeEach
     void setUp() throws Exception {
-        taskManager = new TaskManagerImpl(applicationContext);
+        taskManager = new TaskManagerImpl(applicationContext, mock(TaskRepository.class));
 
         Field taskServiceField = TaskManagerImpl.class.getDeclaredField("taskService");
         taskServiceField.setAccessible(true);

src/test/java/me/bobert/netneutrality/db/AbstractRepositoryTest.java

@@ -0,0 +1,105 @@
+package me.bobert.netneutrality.db;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import me.bobert.netneutrality.db.entities.OBlacklist;
+import me.bobert.netneutrality.db.entities.OGuild;
+import me.bobert.netneutrality.db.repository.BlacklistRepository;
+import me.bobert.netneutrality.db.repository.GuildRepository;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class AbstractRepositoryTest extends MySqlTestBase {
+
+    private GuildRepository guilds;
+    private BlacklistRepository blacklist;
+
+    @BeforeEach
+    void setUp() {
+        guilds = new GuildRepository(sessions());
+        blacklist = new BlacklistRepository(sessions());
+    }
+
+    @Test
+    void stringIdsFindAndDelete() {
+        guilds.findOrCreate("guild-1");
+
+        assertTrue(guilds.findById("guild-1").isPresent());
+        assertEquals(1, guilds.findAll().size());
+        assertTrue(guilds.deleteById("guild-1"));
+        assertTrue(guilds.findById("guild-1").isEmpty());
+        assertFalse(guilds.deleteById("guild-1"));
+    }
+
+    @Test
+    void integerIdsFindAndDelete() {
+        guilds.findOrCreate("guild-1");
+        blacklist.enableWord("guild-1", "user-1", "foo");
+        Integer id = blacklist.findByGuildId("guild-1").getFirst().getId();
+
+        assertEquals("foo", blacklist.findById(id).orElseThrow().getWord());
+        assertTrue(blacklist.deleteById(id));
+        assertTrue(blacklist.findById(id).isEmpty());
+    }
+
+    @Test
+    void saveReturnsMergedState() {
+        OGuild guild = guilds.findOrCreate("guild-1");
+        guild.setDebug(false);
+
+        OGuild saved = guilds.save(guild);
+
+        assertFalse(saved.getDebug());
+        assertFalse(guilds.findById("guild-1").orElseThrow().getDebug());
+    }
+
+    @Test
+    void failingWriteThrowsAndRollsBack() {
+        RuntimeException failure = new IllegalStateException("boom");
+        FailingGuildRepository failing = new FailingGuildRepository(sessions());
+
+        RuntimeException thrown = assertThrows(RuntimeException.class, () -> failing.insertThenFail("guild-1", failure));
+
+        assertEquals(failure, thrown);
+        assertTrue(guilds.findById("guild-1").isEmpty());
+    }
+
+    @Test
+    void constraintViolationPropagates() {
+        OGuild missing = new OGuild();
+        missing.setGuildId("does-not-exist");
+        OBlacklist orphan = new OBlacklist();
+        orphan.setGuild(missing);
+        orphan.setWord("foo");
+        orphan.setCreatorId("user-1");
+        orphan.setEnabled(true);
+
+        assertThrows(RuntimeException.class, () -> blacklist.save(orphan));
+        assertTrue(blacklist.findAll().isEmpty());
+    }
+
+    private static final class FailingGuildRepository extends AbstractRepository<OGuild, String> {
+        FailingGuildRepository(SessionProvider sessions) {
+            super(sessions, OGuild.class);
+        }
+
+        void insertThenFail(String guildId, RuntimeException failure) {
+            writeVoid(session -> {
+                OGuild guild = new OGuild();
+                guild.setGuildId(guildId);
+                session.persist(guild);
+                session.flush();
+                throw failure;
+            });
+        }
+    }
+}

src/test/java/me/bobert/netneutrality/db/DbLayeringTest.java

@@ -0,0 +1,61 @@
+package me.bobert.netneutrality.db;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+
+/**
+ * Keeps the persistence layer free of Discord (JDA) and command-framework types.
+ */
+class DbLayeringTest {
+
+    private static final Path DB_SOURCES = Path.of("src/main/java/me/bobert/netneutrality/db");
+    private static final List<String> FORBIDDEN = List.of(
+        "import net.dv8tion.jda.",
+        "import me.bobert.netneutrality.core.command."
+    );
+
+    @Test
+    void servicesAndRepositoriesDoNotImportJdaOrCommandTypes() throws IOException {
+        List<String> violations;
+        try (Stream<Path> files = Stream.concat(Files.walk(DB_SOURCES.resolve("service")), Files.walk(DB_SOURCES.resolve("repository")))) {
+            violations = files
+                .filter(path -> path.toString().endsWith(".java"))
+                .flatMap(DbLayeringTest::violations)
+                .toList();
+        }
+
+        assertEquals(List.of(), violations);
+    }
+
+    @Test
+    void scanFindsSources() throws IOException {
+        try (Stream<Path> files = Files.walk(DB_SOURCES.resolve("service"))) {
+            assertFalse(files.filter(path -> path.toString().endsWith(".java")).toList().isEmpty());
+        }
+    }
+
+    private static Stream<String> violations(Path file) {
+        try {
+            return Files.readAllLines(file).stream()
+                .map(String::trim)
+                .filter(line -> FORBIDDEN.stream().anyMatch(line::startsWith))
+                .map(line -> file.getFileName() + ": " + line);
+        } catch (IOException e) {
+            throw new IllegalStateException(e);
+        }
+    }
+}

src/test/java/me/bobert/netneutrality/db/MySqlTestBase.java

@@ -0,0 +1,69 @@
+package me.bobert.netneutrality.db;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.BeforeEach;
+import org.testcontainers.junit.jupiter.Testcontainers;
+import org.testcontainers.mysql.MySQLContainer;
+
+import java.util.List;
+
+/**
+ * Shared base for database integration tests.
+ *
+ * <p>Starts one throwaway MySQL 8 container for the whole test run and a real {@link SessionManager}
+ * on top of it, so Flyway migrations and Hibernate schema validation run exactly as in production.
+ * Tests are skipped when Docker is not available. Every table is emptied before each test.
+ */
+@Testcontainers(disabledWithoutDocker = true)
+public abstract class MySqlTestBase {
+
+    private static final List<String> TABLES = List.of(
+        "blacklist", "guild_settings", "logging", "log_message", "tasks", "web_users", "guilds");
+
+    private static MySQLContainer mysql;
+    private static SessionManager sessionManager;
+
+    @BeforeAll
+    static void startDatabase() {
+        synchronized (MySqlTestBase.class) {
+            if (sessionManager != null) {
+                return;
+            }
+            // V1 runs CREATE DATABASE, so connect as root to the real schema name.
+            mysql = new MySQLContainer("mysql:8.4")
+                .withDatabaseName("netneutrality")
+                .withUsername("root")
+                .withPassword("test");
+            mysql.start();
+
+            SessionManager manager = new SessionManager(databaseConfig(), false);
+            manager.start();
+            sessionManager = manager;
+        }
+    }
+
+    protected static DatabaseConfig databaseConfig() {
+        return new DatabaseConfig(mysql.getJdbcUrl(), mysql.getUsername(), mysql.getPassword());
+    }
+
+    protected static SessionManager sessions() {
+        return sessionManager;
+    }
+
+    @BeforeEach
+    void cleanDatabase() {
+        sessionManager.getSessionFactory().inTransaction(session -> {
+            session.createNativeMutationQuery("SET FOREIGN_KEY_CHECKS = 0").executeUpdate();
+            for (String table : TABLES) {
+                session.createNativeMutationQuery("DELETE FROM `" + table + "`").executeUpdate();
+            }
+            session.createNativeMutationQuery("SET FOREIGN_KEY_CHECKS = 1").executeUpdate();
+        });
+    }
+}

src/test/java/me/bobert/netneutrality/db/SessionManagerLifecycleTest.java

@@ -0,0 +1,34 @@
+package me.bobert.netneutrality.db;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+/**
+ * Database-free checks of the {@link SessionManager} / {@link DatabaseConfig} contract.
+ */
+class SessionManagerLifecycleTest {
+
+    @Test
+    void getSessionFactoryBeforeStartThrows() {
+        SessionManager manager = new SessionManager(new DatabaseConfig("jdbc:mysql://localhost/x", "u", "p"), false);
+
+        assertThrows(IllegalStateException.class, manager::getSessionFactory);
+        assertDoesNotThrow(manager::stop);
+    }
+
+    @Test
+    void configNeverPrintsPassword() {
+        DatabaseConfig config = new DatabaseConfig("jdbc:mysql://localhost/x", "user", "hunter2");
+
+        assertFalse(config.toString().contains("hunter2"));
+    }
+}

src/test/java/me/bobert/netneutrality/db/SessionManagerTest.java

@@ -0,0 +1,36 @@
+package me.bobert.netneutrality.db;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+class SessionManagerTest extends MySqlTestBase {
+
+    @Test
+    void startAppliesMigrationsAndValidatesSchema() {
+        assertFalse(sessions().getSessionFactory().isClosed());
+
+        Long applied = sessions().getSessionFactory().fromSession(session -> session
+            .createNativeQuery("SELECT COUNT(*) FROM flyway_schema_history WHERE success = 1", Long.class)
+            .getSingleResult());
+        assertEquals(2L, applied);
+    }
+
+    @Test
+    void startFailsClearlyForUnreachableDatabase() {
+        SessionManager manager = new SessionManager(
+            new DatabaseConfig("jdbc:mysql://localhost:1/none?connectTimeout=500", "nobody", "secret"), false);
+
+        IllegalStateException e = assertThrows(IllegalStateException.class, manager::start);
+        assertEquals("Unable to connect to the database", e.getMessage());
+        assertThrows(IllegalStateException.class, manager::getSessionFactory);
+    }
+}

src/test/java/me/bobert/netneutrality/db/entities/EntityEqualityTest.java

@@ -0,0 +1,60 @@
+package me.bobert.netneutrality.db.entities;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import org.junit.jupiter.api.Test;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class EntityEqualityTest {
+
+    @Test
+    void sameIdIsEqual() {
+        OBlacklist a = new OBlacklist();
+        a.setId(1);
+        OBlacklist b = new OBlacklist();
+        b.setId(1);
+
+        assertEquals(a, b);
+        assertEquals(a.hashCode(), b.hashCode());
+    }
+
+    @Test
+    void transientInstancesAreOnlyEqualToThemselves() {
+        OBlacklist a = new OBlacklist();
+        OBlacklist b = new OBlacklist();
+
+        assertEquals(a, a);
+        assertNotEquals(a, b);
+    }
+
+    @Test
+    void hashIsStableWhenIdIsAssigned() {
+        OGuildSetting setting = new OGuildSetting();
+        Set<OGuildSetting> set = new HashSet<>();
+        set.add(setting);
+
+        setting.setId(42);
+
+        assertTrue(set.contains(setting));
+    }
+
+    @Test
+    void differentTypesAreNotEqual() {
+        OGuild guild = new OGuild();
+        guild.setGuildId("1");
+        OWebUser user = new OWebUser();
+        user.setId("1");
+
+        assertNotEquals(guild, user);
+    }
+}

src/test/java/me/bobert/netneutrality/db/repository/BlacklistRepositoryTest.java

@@ -0,0 +1,76 @@
+package me.bobert.netneutrality.db.repository;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import me.bobert.netneutrality.db.MySqlTestBase;
+import me.bobert.netneutrality.db.entities.OBlacklist;
+import me.bobert.netneutrality.db.repository.BlacklistRepository.EnableOutcome;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.Set;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class BlacklistRepositoryTest extends MySqlTestBase {
+    private static final String GUILD = "guild-1";
+
+    private BlacklistRepository blacklist;
+    private GuildRepository guilds;
+
+    @BeforeEach
+    void setUp() {
+        blacklist = new BlacklistRepository(sessions());
+        guilds = new GuildRepository(sessions());
+        guilds.findOrCreate(GUILD);
+    }
+
+    @Test
+    void addThenDeleteRemovesRow() {
+        assertEquals(EnableOutcome.CREATED, blacklist.enableWord(GUILD, "user-1", "foo"));
+        assertEquals(Set.of("foo"), blacklist.findEnabledWords(GUILD));
+
+        // Regression: the delete used to run on a detached entity and silently fail.
+        assertTrue(blacklist.deleteWord(GUILD, "FOO"));
+        assertTrue(blacklist.findByGuildId(GUILD).isEmpty());
+        assertFalse(blacklist.deleteWord(GUILD, "foo"));
+    }
+
+    @Test
+    void addingExistingWordIsUnchanged() {
+        blacklist.enableWord(GUILD, "user-1", "foo");
+
+        assertEquals(EnableOutcome.UNCHANGED, blacklist.enableWord(GUILD, "user-2", "Foo"));
+        assertEquals(1, blacklist.findByGuildId(GUILD).size());
+    }
+
+    @Test
+    void addingDisabledWordReenablesIt() {
+        OBlacklist disabled = new OBlacklist();
+        disabled.setGuild(guilds.findById(GUILD).orElseThrow());
+        disabled.setWord("bar");
+        disabled.setCreatorId("user-1");
+        disabled.setEnabled(false);
+        blacklist.save(disabled);
+        assertTrue(blacklist.findEnabledWords(GUILD).isEmpty());
+
+        assertEquals(EnableOutcome.ENABLED, blacklist.enableWord(GUILD, "user-2", "bar"));
+        assertEquals(Set.of("bar"), blacklist.findEnabledWords(GUILD));
+        assertEquals(1, blacklist.findByGuildId(GUILD).size());
+    }
+
+    @Test
+    void wordsAreScopedPerGuild() {
+        guilds.findOrCreate("guild-2");
+        blacklist.enableWord(GUILD, "user-1", "foo");
+
+        assertTrue(blacklist.findEnabledWords("guild-2").isEmpty());
+        assertFalse(blacklist.deleteWord("guild-2", "foo"));
+    }
+}

src/test/java/me/bobert/netneutrality/db/repository/GuildSettingRepositoryTest.java

@@ -0,0 +1,70 @@
+package me.bobert.netneutrality.db.repository;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import me.bobert.netneutrality.db.GSettings;
+import me.bobert.netneutrality.db.MySqlTestBase;
+import me.bobert.netneutrality.db.entities.OGuildSetting;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class GuildSettingRepositoryTest extends MySqlTestBase {
+    private static final String GUILD = "guild-1";
+
+    private GuildSettingRepository settings;
+
+    @BeforeEach
+    void setUp() {
+        settings = new GuildSettingRepository(sessions());
+        new GuildRepository(sessions()).findOrCreate(GUILD);
+    }
+
+    @Test
+    void setUpdateAndResetPersist() {
+        settings.upsertOrDelete(GUILD, GSettings.MUSIC_VOLUME, "50");
+        assertEquals("50", single().getValue());
+
+        // Regression: updates used to run without a transaction and were never committed.
+        settings.upsertOrDelete(GUILD, GSettings.MUSIC_VOLUME, "70");
+        assertEquals("70", single().getValue());
+
+        settings.upsertOrDelete(GUILD, GSettings.MUSIC_VOLUME, GSettings.MUSIC_VOLUME.getDefaultValue());
+        assertTrue(settings.findByGuild(GUILD).isEmpty());
+    }
+
+    @Test
+    void nullValueDeletesSetting() {
+        settings.upsertOrDelete(GUILD, GSettings.MUSIC_ROLE, "role-1");
+
+        settings.upsertOrDelete(GUILD, GSettings.MUSIC_ROLE, null);
+
+        assertTrue(settings.findByGuild(GUILD).isEmpty());
+    }
+
+    @Test
+    void settingsAreIndependent() {
+        settings.upsertOrDelete(GUILD, GSettings.MUSIC_ROLE, "role-1");
+        settings.upsertOrDelete(GUILD, GSettings.MUSIC_CHANNEL, "channel-1");
+
+        settings.upsertOrDelete(GUILD, GSettings.MUSIC_ROLE, null);
+
+        OGuildSetting remaining = single();
+        assertEquals(GSettings.MUSIC_CHANNEL.getName(), remaining.getName());
+        assertEquals("channel-1", remaining.getValue());
+    }
+
+    private OGuildSetting single() {
+        List<OGuildSetting> all = settings.findByGuild(GUILD);
+        assertEquals(1, all.size());
+        return all.getFirst();
+    }
+}

src/test/java/me/bobert/netneutrality/db/repository/MessageRepositoryTest.java

@@ -0,0 +1,64 @@
+package me.bobert.netneutrality.db.repository;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import me.bobert.netneutrality.db.MySqlTestBase;
+import me.bobert.netneutrality.db.entities.OLogMessage;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.time.Instant;
+import java.time.temporal.ChronoUnit;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class MessageRepositoryTest extends MySqlTestBase {
+    private static final String GUILD = "guild-1";
+
+    private MessageRepository messages;
+
+    @BeforeEach
+    void setUp() {
+        messages = new MessageRepository(sessions());
+        new GuildRepository(sessions()).findOrCreate(GUILD);
+    }
+
+    @Test
+    void unknownMessageIsEmpty() {
+        assertTrue(messages.findByMessageId("nope").isEmpty());
+        assertTrue(messages.findMessageContent("nope").isEmpty());
+        assertFalse(messages.updateEditedMessage("nope", "edited"));
+    }
+
+    @Test
+    void logAndEdit() {
+        messages.log(GUILD, "channel-1", "user-1", "message-1", "  hello  ", Instant.now());
+
+        assertEquals("hello", messages.findMessageContent("message-1").orElseThrow());
+        assertTrue(messages.updateEditedMessage("message-1", "hello!"));
+        assertEquals("hello!", messages.findByMessageId("message-1").orElseThrow().getEditedMessage());
+
+        assertTrue(messages.deleteByMessageId("message-1"));
+        assertTrue(messages.findByMessageId("message-1").isEmpty());
+    }
+
+    @Test
+    void findByUserReturnsNewestFirst() {
+        Instant now = Instant.now().truncatedTo(ChronoUnit.SECONDS);
+        messages.log(GUILD, "c", "user-1", "old", "old", now.minusSeconds(60));
+        messages.log(GUILD, "c", "user-1", "new", "new", now);
+        messages.log(GUILD, "c", "user-1", "mid", "mid", now.minusSeconds(30));
+        messages.log(GUILD, "c", "user-2", "other", "other", now);
+
+        List<String> ids = messages.findByUser("user-1", GUILD, 2).stream().map(OLogMessage::getMessageId).toList();
+
+        assertEquals(List.of("new", "mid"), ids);
+    }
+}

src/test/java/me/bobert/netneutrality/db/repository/TaskRepositoryTest.java

@@ -0,0 +1,46 @@
+package me.bobert.netneutrality.db.repository;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import me.bobert.netneutrality.db.MySqlTestBase;
+import me.bobert.netneutrality.db.entities.OTask;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class TaskRepositoryTest extends MySqlTestBase {
+
+    private TaskRepository tasks;
+
+    @BeforeEach
+    void setUp() {
+        tasks = new TaskRepository(sessions());
+    }
+
+    @Test
+    void upsertInsertsThenUpdates() {
+        tasks.upsert("task-1", "emoji-reaction-role", "{\"v\":1}");
+        tasks.upsert("task-1", "emoji-reaction-role", "{\"v\":2}");
+
+        assertEquals(1, tasks.findAll().size());
+        OTask stored = tasks.findByTaskId("task-1").orElseThrow();
+        assertEquals("{\"v\":2}", stored.getPayload());
+        assertEquals("emoji-reaction-role", stored.getTaskClass());
+    }
+
+    @Test
+    void deleteByTaskId() {
+        tasks.upsert("task-1", "type", "{}");
+
+        assertTrue(tasks.deleteByTaskId("task-1"));
+        assertTrue(tasks.findByTaskId("task-1").isEmpty());
+        assertFalse(tasks.deleteByTaskId("task-1"));
+    }
+}

src/test/java/me/bobert/netneutrality/db/service/BlacklistServiceTest.java

@@ -0,0 +1,54 @@
+package me.bobert.netneutrality.db.service;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import me.bobert.netneutrality.db.MySqlTestBase;
+import me.bobert.netneutrality.db.repository.BlacklistRepository;
+import me.bobert.netneutrality.db.repository.GuildRepository;
+import me.bobert.netneutrality.db.repository.GuildSettingRepository;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class BlacklistServiceTest extends MySqlTestBase {
+
+    private BlacklistService service;
+
+    @BeforeEach
+    void setUp() {
+        GuildService guildService = new GuildService("guild-1", new GuildRepository(sessions()),
+            new BlacklistRepository(sessions()), new GuildSettingRepository(sessions()));
+        service = guildService.getBlacklistService();
+    }
+
+    @Test
+    void resultSequence() {
+        assertEquals(BlacklistResult.ADDED, service.add("user-1", "foo"));
+        assertEquals(BlacklistResult.ALREADY_EXISTS, service.add("user-1", "foo"));
+        assertEquals(BlacklistResult.REMOVED, service.remove("foo"));
+        assertEquals(BlacklistResult.NOT_FOUND, service.remove("foo"));
+    }
+
+    @Test
+    void cacheFollowsChanges() {
+        service.add("user-1", "Foo");
+
+        assertEquals(List.of(new BlacklistEntry("Foo", true)), service.list());
+        assertTrue(service.containsBlacklistedWord("well, FOO bar"));
+        assertFalse(service.containsBlacklistedWord("foobar"));
+
+        service.remove("foo");
+
+        assertFalse(service.containsBlacklistedWord("foo"));
+        assertTrue(service.list().isEmpty());
+    }
+}

src/test/java/me/bobert/netneutrality/db/service/GuildServiceProviderImplTest.java

@@ -0,0 +1,53 @@
+package me.bobert.netneutrality.db.service;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import me.bobert.netneutrality.db.repository.BlacklistRepository;
+import me.bobert.netneutrality.db.repository.GuildRepository;
+import me.bobert.netneutrality.db.repository.GuildSettingRepository;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertNotSame;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.mock;
+
+class GuildServiceProviderImplTest {
+
+    private GuildServiceProviderImpl provider;
+
+    @BeforeEach
+    void setUp() {
+        provider = new GuildServiceProviderImpl(mock(GuildRepository.class), mock(BlacklistRepository.class),
+            mock(GuildSettingRepository.class));
+    }
+
+    @Test
+    void getCachesPerGuild() {
+        assertSame(provider.get("guild-1"), provider.get("guild-1"));
+        assertNotSame(provider.get("guild-1"), provider.get("guild-2"));
+    }
+
+    @Test
+    void evictBuildsNewServiceOnNextGet() {
+        GuildService first = provider.get("guild-1");
+
+        provider.evict("guild-1");
+
+        assertTrue(provider.snapshot().isEmpty());
+        assertNotSame(first, provider.get("guild-1"));
+    }
+
+    @Test
+    void snapshotIsReadOnly() {
+        provider.get("guild-1");
+
+        assertThrows(UnsupportedOperationException.class, () -> provider.snapshot().clear());
+    }
+}

src/test/java/me/bobert/netneutrality/db/service/GuildServiceTest.java

@@ -0,0 +1,71 @@
+package me.bobert.netneutrality.db.service;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import me.bobert.netneutrality.db.GSettings;
+import me.bobert.netneutrality.db.MySqlTestBase;
+import me.bobert.netneutrality.db.repository.BlacklistRepository;
+import me.bobert.netneutrality.db.repository.GuildRepository;
+import me.bobert.netneutrality.db.repository.GuildSettingRepository;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class GuildServiceTest extends MySqlTestBase {
+
+    private GuildRepository guilds;
+    private BlacklistRepository blacklist;
+    private GuildSettingRepository settings;
+
+    @BeforeEach
+    void setUp() {
+        guilds = new GuildRepository(sessions());
+        blacklist = new BlacklistRepository(sessions());
+        settings = new GuildSettingRepository(sessions());
+    }
+
+    private GuildService newService(String guildId) {
+        return new GuildService(guildId, guilds, blacklist, settings);
+    }
+
+    @Test
+    void findOrCreateGuildCreatesOnce() {
+        GuildService service = newService("guild-1");
+
+        service.findOrCreateGuild("guild-1");
+        newService("guild-1");
+
+        assertEquals(1, guilds.findAll().size());
+        assertTrue(service.isDebugEnabled());
+    }
+
+    @Test
+    void updateDebugModePersists() {
+        GuildService service = newService("guild-1");
+
+        service.updateDebugMode(false);
+
+        assertFalse(service.isDebugEnabled());
+        assertFalse(guilds.findById("guild-1").orElseThrow().getDebug());
+    }
+
+    @Test
+    void writesRecreateDeletedGuild() {
+        GuildService service = newService("guild-1");
+        service.deleteGuild();
+        assertTrue(guilds.findById("guild-1").isEmpty());
+
+        // Replaces the old tryLoad side channel: the cached service recreates its row on write.
+        service.getGuildSettingService().set(GSettings.MUSIC_VOLUME, "55");
+
+        assertTrue(guilds.findById("guild-1").isPresent());
+        assertEquals("55", service.getGuildSettingService().getOrDefault(GSettings.MUSIC_VOLUME));
+    }
+}

src/test/java/me/bobert/netneutrality/db/service/GuildSettingServiceTest.java

@@ -0,0 +1,99 @@
+package me.bobert.netneutrality.db.service;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import me.bobert.netneutrality.db.GSettings;
+import me.bobert.netneutrality.db.entities.OGuildSetting;
+import me.bobert.netneutrality.db.repository.GuildSettingRepository;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+class GuildSettingServiceTest {
+
+    private GuildService guildService;
+    private GuildSettingRepository repository;
+
+    @BeforeEach
+    void setUp() {
+        guildService = mock(GuildService.class);
+        repository = mock(GuildSettingRepository.class);
+        when(guildService.getGuildId()).thenReturn("guild-1");
+    }
+
+    @Test
+    void readersNeverSeeEmptyCacheDuringReload() throws Exception {
+        CountDownLatch reloading = new CountDownLatch(1);
+        CountDownLatch release = new CountDownLatch(1);
+        when(repository.findByGuild("guild-1"))
+            .thenReturn(List.of(setting(GSettings.MUSIC_VOLUME, "50")))
+            .thenAnswer(invocation -> {
+                reloading.countDown();
+                assertTrue(release.await(5, TimeUnit.SECONDS));
+                return List.of(setting(GSettings.MUSIC_VOLUME, "70"));
+            });
+        GuildSettingService service = new GuildSettingService(guildService, repository);
+
+        CompletableFuture<Void> reload = CompletableFuture.runAsync(service::reloadSettingsCache);
+        assertTrue(reloading.await(5, TimeUnit.SECONDS));
+
+        // While the reload is in flight, readers still get the previous, complete snapshot.
+        assertEquals("50", service.getOrDefault(GSettings.MUSIC_VOLUME));
+        assertEquals(Map.of("MUSIC_VOLUME", "50"), service.snapshot());
+
+        release.countDown();
+        reload.get(5, TimeUnit.SECONDS);
+        assertEquals("70", service.getOrDefault(GSettings.MUSIC_VOLUME));
+    }
+
+    @Test
+    void settingsSnapshotIsUnmodifiable() {
+        when(repository.findByGuild("guild-1")).thenReturn(List.of(setting(GSettings.MUSIC_ROLE, "role-1")));
+        GuildSettingService service = new GuildSettingService(guildService, repository);
+
+        assertThrows(UnsupportedOperationException.class, () -> service.snapshot().put("x", "y"));
+    }
+
+    @Test
+    void missingSettingFallsBackToDefault() {
+        when(repository.findByGuild("guild-1")).thenReturn(List.of());
+        GuildSettingService service = new GuildSettingService(guildService, repository);
+
+        assertEquals(GSettings.MUSIC_MAXPLAYLISTSIZE.getDefaultValue(), service.getOrDefault(GSettings.MUSIC_MAXPLAYLISTSIZE));
+        assertTrue(service.get(GSettings.MUSIC_MAXPLAYLISTSIZE).isEmpty());
+    }
+
+    @Test
+    void setEnsuresGuildAndWritesThrough() {
+        when(repository.findByGuild("guild-1")).thenReturn(List.of());
+        GuildSettingService service = new GuildSettingService(guildService, repository);
+
+        service.set(GSettings.MUSIC_VOLUME, "40");
+
+        verify(guildService).ensureEntity();
+        verify(repository).upsertOrDelete("guild-1", GSettings.MUSIC_VOLUME, "40");
+    }
+
+    private static OGuildSetting setting(GSettings key, String value) {
+        OGuildSetting setting = new OGuildSetting();
+        setting.setName(key.getName());
+        setting.setValue(value);
+        return setting;
+    }
+}

src/test/java/me/bobert/netneutrality/db/service/TaskServiceTest.java

@@ -0,0 +1,63 @@
+package me.bobert.netneutrality.db.service;
+
+/*
+ * Copyright (c) anthorob
+ *
+ * https://discord.gg/qUa6zNFZsd
+ */
+
+import me.bobert.netneutrality.core.tasks.PersistableTask;
+import me.bobert.netneutrality.core.tasks.TaskManager;
+import me.bobert.netneutrality.core.tasks.persistence.PersistableTaskRegistry;
+import me.bobert.netneutrality.db.repository.TaskRepository;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoInteractions;
+import static org.mockito.Mockito.when;
+
+class TaskServiceTest {
+
+    private PersistableTaskRegistry registry;
+    private TaskRepository repository;
+    private TaskService service;
+    private PersistableTask task;
+
+    @BeforeEach
+    void setUp() {
+        registry = mock(PersistableTaskRegistry.class);
+        repository = mock(TaskRepository.class);
+        service = new TaskService(mock(TaskManager.class), registry, repository);
+        task = mock(PersistableTask.class);
+        when(task.getId()).thenReturn("task-1");
+        when(task.typeId()).thenReturn("some-type");
+    }
+
+    @Test
+    void persistUnregisteredTypeIsNoop() {
+        when(registry.isRegistered("some-type")).thenReturn(false);
+
+        service.persistTask(task);
+
+        verifyNoInteractions(repository);
+    }
+
+    @Test
+    void persistRegisteredTypeUpserts() {
+        when(registry.isRegistered("some-type")).thenReturn(true);
+        when(task.toPayload()).thenReturn("{}");
+
+        service.persistTask(task);
+
+        verify(repository).upsert("task-1", "some-type", "{}");
+    }
+
+    @Test
+    void unpersistDeletesByTaskId() {
+        service.unpersistTask(task);
+
+        verify(repository).deleteByTaskId("task-1");
+    }
+}

src/test/java/me/bobert/netneutrality/http/server/WebApiTest.java

@@ -58,13 +58,13 @@ class WebApiTest {
         when(jda.getGatewayPing()).thenReturn(12L);
 
         settingService = mock(GuildSettingService.class);
-        when(settingService.getSettings()).thenReturn(Map.of("prefix", "ü!"));
+        when(settingService.snapshot()).thenReturn(Map.of("prefix", "ü!"));
 
         GuildService guildService = mock(GuildService.class);
         when(guildService.getGuildSettingService()).thenReturn(settingService);
 
         GuildServiceProvider provider = mock(GuildServiceProvider.class);
-        when(provider.get(guild)).thenReturn(guildService);
+        when(provider.get(GUILD_ID)).thenReturn(guildService);
 
         SettingsProvider settings = mock(SettingsProvider.class);
         when(settings.get("NETNEUTRALITY_API_PORT", "9000")).thenReturn(String.valueOf(port));