在ActiveMQ中，CORE是最初实现的协议，而AMQP则是后来添加的协议。AMQP是一种标准开放性协议，为使用不同语言和框架的应用程序提供了可靠的异步消息传递。CORE协议则是ActiveMQ专有的协议，它使用jms框架并提供了广泛的功能和可用性。

以下是使用AMQP协议发送和接收消息的简单示例：

import org.apache.qpid.protonj2.client.*;
import org.apache.qpid.protonj2.types.messaging.Message;

public class AmqpProducer {
    public static void main(String[] args) throws Exception {
        String host = "localhost";
        int port = 5672;
        String address = "queue";
        String messageBody = "Hello, AMQP!";

        ProtonClientOptions options = new ProtonClientOptions().setSsl(false);
        ProtonClient client = ProtonClient.create(options);

        client.connect(host, port).block();

        ProtonConnection connection = client.connect(host, port).block();
        ProtonSender sender = connection.createSender(address);

        Message message = Message.Factory.create();
        message.setBody(messageBody);

        sender.send(message).block();

        sender.close();
        client.close();
    }
}

public class AmqpConsumer {
    public static void main(String[] args) throws Exception {
        String host = "localhost";
        int port = 5672;
        String address = "queue";

        ProtonClientOptions options = new ProtonClientOptions().setSsl(false);
        ProtonClient client = ProtonClient.create(options);

        client.connect(host, port).block();

        ProtonConnection connection = client.connect(host, port).block();
        ProtonReceiver receiver = connection.createReceiver(address);

        receiver.open().block();

        Message message = receiver.receive().block();

        if (message != null) {
            System.out.printf("Message received: %s\n", message.getBody());
            receiver.accept(message).block();
        } else {
            System.out.println("No message received.");
        }

        receiver.close();
        client.close();
    }
}

这些示例使用ProtonJ，这是一种使用AMQP 1.0协议与消息代理交互的Java库。这里的代码包括一个简单的生产者，它将一条消息发送到队列，并且一个简单的消费者来接收这条消息。这里的AMQP协议提供