[java] Add QUEUE_DEFAULT constant like other languages

java/API.md

@@ -19,6 +19,7 @@ Java exposes every Go helper. Stored values and protocol behavior still follow G
 | `ResumableSetStepTx`, `ResumableSetStepCursorTx` | `WorkContext.checkpoint(connection[, cursor])` | Checkpoints commit with application writes; failed transactions leave the last committed progress intact. |
 | Worker timeout | `Workers.Handler.timeout(job)` | A default method preserves lambda handlers; per-job overrides also govern rescue decisions. |
 | Retry policy | `RetryPolicy` | A lambda receives the full job and returns `Duration`; the default uses the same error-count backoff and jitter. |
+| `QueueDefault` | `Client.QUEUE_DEFAULT` | The default queue name, `"default"`, used when neither insert options nor job-type defaults specify a queue. |
 | `Queues`, queue CRUD/control APIs | `RunHandle.addQueue/removeQueue`, `Client.queues()` | Runtime concurrency and persisted queue state have separate owners. Reads and mutations support caller transactions. |
 | `Subscribe`, `EventKind`, `Event` | `Client.subscribe`, `EventKind`, `Event`, `Subscription` | Enum filters and an `AutoCloseable` subscription replace channels. Callbacks are synchronous; queue events include their queue. |
 | Periodic jobs and schedules | `Client.Builder.periodic`, `RunHandle.periodicJobs()`, `PeriodicJobBundle`, `PeriodicJob`, `Schedule` | Java time types and a functional scheduling interface; cron implementation details are package-private. |

java/CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Expose `Client.QUEUE_DEFAULT` (`"default"`) for queue configuration and operations, matching the default queue constant in other River clients.
+
 ## [0.2.0] - 2026-10-26
 
 ### Changed

java/README.md

@@ -58,7 +58,7 @@ public class Example {
           System.out.println("Sending " + context.args().subject() + " to " + context.args().address());
           context.output("sent");
         });
-    var client = Client.builder(database).queue("default", 10).workers(workers).build();
+    var client = Client.builder(database).queue(Client.QUEUE_DEFAULT, 10).workers(workers).build();
     var completed = new CompletableFuture<Client.Event>();
     try (var subscription = client.subscribe(completed::complete, Client.EventKind.JOB_COMPLETED);
         var run = client.start()) {
@@ -274,7 +274,7 @@ time, River reports the problem and uses its default backoff.
 ```java
 var retryingEmail = email.withDefaults(InsertOptions.builder().maxAttempts(10).build());
 var clientBuilder = Client.builder(database)
-    .queue("default", 10)
+    .queue(Client.QUEUE_DEFAULT, 10)
     .retryPolicy(job -> Duration.ofSeconds(Math.min(300, 5L * (job.errors().size() + 1))))
     .worker(retryingEmail, context ->
         mailer.send(context.args().address(), context.args().subject()));
@@ -300,7 +300,7 @@ existing job's ID.
 
 ```java
 var email = JobType.of("send_email", SendEmail.class);
-var clientBuilder = Client.builder(database).queue("default", 10);
+var clientBuilder = Client.builder(database).queue(Client.QUEUE_DEFAULT, 10);
 ```
 
 ### Cancelling jobs
@@ -383,7 +383,7 @@ HookWorkEnd reportFailure = (context, failure) -> {
   return failure;
 };
 var clientBuilder = Client.builder(database).plugins(reportFailure)
-    .queue("default", 10)
+    .queue(Client.QUEUE_DEFAULT, 10)
     .errorHandler(failure ->
         System.getLogger("river").log(System.Logger.Level.ERROR, "Runtime failure", failure))
     .worker(email, context -> mailer.send(context.args().address(), context.args().subject()));
@@ -504,9 +504,12 @@ not capture SLF4J or `System.Logger` output automatically.
 different workloads. Set a queue at insertion and configure its worker count.
 The count is local to each runtime; it is not a cluster-wide concurrency limit.
 
+`Client.QUEUE_DEFAULT` is the default queue name, `"default"`. Jobs use it when
+neither insertion options nor job-type defaults specify a queue.
+
 ```java
 var clientBuilder = Client.builder(database)
-    .queue("default", 10)
+    .queue(Client.QUEUE_DEFAULT, 10)
     .queue("mail", 4)
     .worker(email, context -> mailer.send(context.args().address(), context.args().subject()));
 client.insert(email, new SendEmail("hello@example.com", "Welcome"),
@@ -551,7 +554,7 @@ languages match only when they use the same time-zone data.
 
 ```java
 var clientBuilder = Client.builder(database)
-    .queue("default", 10)
+    .queue(Client.QUEUE_DEFAULT, 10)
     .worker(email, context -> mailer.send(context.args().address(), context.args().subject()))
     .periodic("hourly-status", Schedule.every(Duration.ofHours(1)), email,
         new SendEmail("ops@example.com", "Hourly status"), InsertOptions.defaults(), true)
@@ -718,7 +721,7 @@ void completes(@org.junit.jupiter.api.io.TempDir java.nio.file.Path directory) t
   var database = Database.connect("jdbc:sqlite:" + directory.resolve("river.db"));
   new Migrator(database).migrate();
   var client = Client.builder(database)
-      .queue("default", 1)
+      .queue(Client.QUEUE_DEFAULT, 1)
       .worker(echo, context -> context.output(context.args().message()))
       .build();
   var completed = new java.util.concurrent.CompletableFuture<Client.Event>();
@@ -850,7 +853,7 @@ consuming an attempt. `awaitCancellation()` only waits for the signal.
 
 ```java
 var client = Client.builder(database)
-    .queue("default", 10)
+    .queue(Client.QUEUE_DEFAULT, 10)
     .stopTimeout(Duration.ofSeconds(30))
     .worker(email, context -> mailer.send(context.args().address(), context.args().subject()))
     .build();
@@ -883,7 +886,7 @@ delays must fit in signed 64-bit nanoseconds, up to about 292 years.
 
 ```java
 var clientBuilder = Client.builder(database)
-    .queue("default", 10)
+    .queue(Client.QUEUE_DEFAULT, 10)
     .retention(Duration.ofDays(1), Duration.ofDays(1), Duration.ofDays(7))
     .worker(email, context -> mailer.send(context.args().address(), context.args().subject()));
 ```

java/conformance/src/main/java/com/riverqueue/conformance/RuntimeAdapter.java

@@ -185,7 +185,9 @@ private void start(Client river, JsonNode params) {
     var builder =
         river.toBuilder()
             .id(params.path("client_id").asString())
-            .queue(params.path("queue").asString("default"), params.path("max_workers").asInt(1))
+            .queue(
+                params.path("queue").asString(Client.QUEUE_DEFAULT),
+                params.path("max_workers").asInt(1))
             .worker(ECHO, this::work)
             .pollOnly(params.path("poll_only").asBoolean(false))
             .pollInterval(Duration.ofMillis(params.path("fetch_poll_interval_ms").asLong(10)))

java/river/src/main/java/com/riverqueue/Client.java

@@ -28,6 +28,9 @@
  * application owns its connection pool; inserting jobs does not require a running client.
  */
 public final class Client {
+  /** Default queue name, used when neither insert options nor job-type defaults specify a queue. */
+  public static final String QUEUE_DEFAULT = "default";
+
   private final Builder config;
   private final String id;
   private final List<Consumer<Event>> subscribers = new CopyOnWriteArrayList<>();

java/river/src/main/java/com/riverqueue/InsertOptions.java

@@ -38,7 +38,7 @@ InsertOptions resolve(InsertOptions fallback) {
         first(metadata, fallback.metadata, Json.object()),
         first(pending, fallback.pending, false),
         first(priority, fallback.priority, 1),
-        first(queue, fallback.queue, "default"),
+        first(queue, fallback.queue, Client.QUEUE_DEFAULT),
         first(scheduledAt, fallback.scheduledAt, null),
         first(tags, fallback.tags, List.of()),
         first(unique, fallback.unique, Unique.none()));
@@ -84,6 +84,7 @@ public Builder priority(int value) {
       return this;
     }
 
+    /** Sets the queue; defaults to the job type's queue or {@link Client#QUEUE_DEFAULT}. */
     public Builder queue(String value) {
       queue = value;
       return this;

java/river/src/test/java/com/riverqueue/ClientLifecycleTest.java

@@ -32,7 +32,7 @@ private Client.Builder builder() {
         .leadership(false)
         .pollInterval(Duration.ofMillis(10))
         .pollOnly(true)
-        .queue("default", 1)
+        .queue(Client.QUEUE_DEFAULT, 1)
         .stopTimeout(Duration.ofSeconds(5));
   }
 
@@ -118,7 +118,7 @@ void failedDatabaseStartupCanBeRetried() throws Exception {
         Client.builder(new Database(source, database.dialect()).withSchema(database.schema()))
             .leadership(false)
             .pollOnly(true)
-            .queue("default", 1)
+            .queue(Client.QUEUE_DEFAULT, 1)
             .workers(new Workers().add(TYPE, context -> {}))
             .build();
     assertEquals(