Add publisher confirms tutorial using ConfirmationChannel

The new `ConfirmationChannel` API introduced in
rabbitmq/rabbitmq-java-client#1824 provides asynchronous publisher
confirmation tracking with a `CompletableFuture`-based API, rate
limiting, and message correlation support.

This change adds `PublisherConfirmsAsync.java` to demonstrate the
`ConfirmationChannel` API. The tutorial shows how to create a
`ConfirmationChannel` wrapper with rate limiting, publish messages
asynchronously with correlation context, and wait for all confirmations
using `CompletableFuture.allOf()`.

Depends on rabbitmq/rabbitmq-java-client#1824

Author: lukebakken

java/PublisherConfirmsAsync.java

@@ -0,0 +1,74 @@
+// Copyright (c) 2007-2025 Broadcom. All Rights Reserved. The term "Broadcom" refers to Broadcom Inc. and/or its subsidiaries.
+//
+// This software, the RabbitMQ Java client library, is triple-licensed under the
+// Mozilla Public License 2.0 ("MPL"), the GNU General Public License version 2
+// ("GPL") and the Apache License version 2 ("ASL"). For the MPL, please see
+// LICENSE-MPL-RabbitMQ. For the GPL, please see LICENSE-GPL2.  For the ASL,
+// please see LICENSE-APACHE2.
+//
+// This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND,
+// either express or implied. See the LICENSE file for specific language governing
+// rights and limitations of this software.
+//
+// If you have any questions regarding licensing, please contact us at
+// [email protected].
+
+import com.rabbitmq.client.*;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+
+/**
+ * Example demonstrating asynchronous publisher confirmations with ConfirmationChannel.
+ */
+public class PublisherConfirmsAsync {
+
+    public static void main(String[] args) throws Exception {
+        ConnectionFactory factory = new ConnectionFactory();
+        factory.setHost("localhost");
+
+        try (Connection connection = factory.newConnection();
+             Channel channel = connection.createChannel()) {
+            
+            // Create ConfirmationChannel with optional rate limiting
+            RateLimiter rateLimiter = new ThrottlingRateLimiter(100); // Max 100 in-flight
+            ConfirmationChannel confirmChannel = ConfirmationChannel.create(channel, rateLimiter);
+            
+            String queueName = confirmChannel.queueDeclare().getQueue();
+
+            // Collect futures for all publishes
+            List<CompletableFuture<String>> futures = new ArrayList<>();
+            
+            // Publish messages asynchronously with context for correlation
+            for (int i = 0; i < 10; i++) {
+                String messageId = "msg-" + i;
+                String message = "Message " + i;
+                
+                CompletableFuture<String> future = confirmChannel.basicPublishAsync(
+                        "",
+                        queueName,
+                        MessageProperties.PERSISTENT_TEXT_PLAIN,
+                        message.getBytes(),
+                        messageId  // Context parameter for correlation
+                );
+
+                // Handle confirmation
+                future.thenAccept(id -> System.out.println("Confirmed: " + id))
+                      .exceptionally(ex -> {
+                          if (ex.getCause() instanceof PublishException) {
+                              PublishException pe = (PublishException) ex.getCause();
+                              System.err.println("Failed: " + pe.getContext() + " - " + ex.getMessage());
+                          }
+                          return null;
+                      });
+                
+                futures.add(future);
+            }
+
+            // Wait for all confirmations
+            CompletableFuture.allOf(futures.toArray(new CompletableFuture[0])).join();
+            System.out.println("All messages published and confirmed");
+        }
+    }
+}

java/run-with-dev-client.sh

@@ -0,0 +1,38 @@
+#!/bin/bash
+# Run a Java tutorial example with the development version of rabbitmq-java-client
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+if (( $# == 0 ))
+then
+    echo "Usage: $0 <ClassName> [args...]" >&2
+    echo "Example: $0 PublisherConfirmsAsync" >&2
+    exit 1
+fi
+
+declare -r class_name="$1"
+shift
+
+declare -r client_dir="../../rabbitmq-java-client"
+declare -r client_jar="$client_dir"/target/amqp-client-*-SNAPSHOT.jar
+
+if [[ ! -f "$client_jar" ]]
+then
+    echo "Building rabbitmq-java-client..." >&2
+    (cd "$client_dir" && ./mvnw clean package -DskipTests)
+fi
+
+echo "Getting compile classpath..." >&2
+
+compile_cp=$(cd "$client_dir" && ./mvnw dependency:build-classpath -DincludeScope=compile 2>&1 | grep -E "^/.*\.jar" | head -1)
+readonly compile_cp
+
+declare -r full_cp=".:$client_jar:$compile_cp"
+
+echo "Compiling ${class_name}.java..." >&2
+javac -cp "$full_cp" "${class_name}.java"
+
+echo "Running $class_name..." >&2
+java -cp "$full_cp" "$class_name" "$@"