Hello World

Using ActiveMQ > Hello World

The following is a very simple JMS application with multiple, concurrent, consumers and producers. See the Initial Configuration guide for details on how to setup your classpath correctly.

Things you might do after running this example:

Setup a broker instead of using the org.activemq.broker.impl.Main class directly
Use JNDI to lookup a javax.jms.ConnectionFactory rather than creating ActiveMQConnectionFactory directly.
Implement the javax.jms.MessageListener interface rather than calling consumer.receive()
Use transactional sessions
Use a Topic rather than a queue

The point of this example is to show you the basic code required to use JMS in a straightforward way. The Consumers and Producers could very easy be on completely different machines or in different processes.

App.java

import org.apache.activemq.ActiveMQConnectionFactory;

import javax.jms.Connection;
import javax.jms.DeliveryMode;
import javax.jms.Destination;
import javax.jms.ExceptionListener;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageProducer;
import javax.jms.Session;
import javax.jms.TextMessage;

/**
 * Hello world!
 */
public class App {

    public static void main(String\[\] args) throws Exception {
        thread(new HelloWorldProducer(), false);
        thread(new HelloWorldProducer(), false);
        thread(new HelloWorldConsumer(), false);
        Thread.sleep(1000);
        thread(new HelloWorldConsumer(), false);
        thread(new HelloWorldProducer(), false);
        thread(new HelloWorldConsumer(), false);
        thread(new HelloWorldProducer(), false);
        Thread.sleep(1000);
        thread(new HelloWorldConsumer(), false);
        thread(new HelloWorldProducer(), false);
        thread(new HelloWorldConsumer(), false);
        thread(new HelloWorldConsumer(), false);
        thread(new HelloWorldProducer(), false);
        thread(new HelloWorldProducer(), false);
        Thread.sleep(1000);
        thread(new HelloWorldProducer(), false);
        thread(new HelloWorldConsumer(), false);
        thread(new HelloWorldConsumer(), false);
        thread(new HelloWorldProducer(), false);
        thread(new HelloWorldConsumer(), false);
        thread(new HelloWorldProducer(), false);
        thread(new HelloWorldConsumer(), false);
        thread(new HelloWorldProducer(), false);
        thread(new HelloWorldConsumer(), false);
        thread(new HelloWorldConsumer(), false);
        thread(new HelloWorldProducer(), false);
    }

    public static void thread(Runnable runnable, boolean daemon) {
        Thread brokerThread = new Thread(runnable);
        brokerThread.setDaemon(daemon);
        brokerThread.start();
    }

    public static class HelloWorldProducer implements Runnable {
        public void run() {
            try {
                // Create a ConnectionFactory
                ActiveMQConnectionFactory connectionFactory = new ActiveMQConnectionFactory("vm://localhost");

                // Create a Connection
                Connection connection = connectionFactory.createConnection();
                connection.start();

                // Create a Session
                Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);

                // Create the destination (Topic or Queue)
                Destination destination = session.createQueue("TEST.FOO");

                // Create a MessageProducer from the Session to the Topic or Queue
                MessageProducer producer = session.createProducer(destination);
                producer.setDeliveryMode(DeliveryMode.NON_PERSISTENT);

                // Create a messages
                String text = "Hello world! From: " + Thread.currentThread().getName() + " : " + this.hashCode();
                TextMessage message = session.createTextMessage(text);

                // Tell the producer to send the message
                System.out.println("Sent message: "+ message.hashCode() + " : " + Thread.currentThread().getName());
                producer.send(message);

                // Clean up
                session.close();
                connection.close();
            }
            catch (Exception e) {
                System.out.println("Caught: " + e);
                e.printStackTrace();
            }
        }
    }

    public static class HelloWorldConsumer implements Runnable, ExceptionListener {
        public void run() {
            try {

                // Create a ConnectionFactory
                ActiveMQConnectionFactory connectionFactory = new ActiveMQConnectionFactory("vm://localhost");

                // Create a Connection
                Connection connection = connectionFactory.createConnection();
                connection.start();

                connection.setExceptionListener(this);

                // Create a Session
                Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);

                // Create the destination (Topic or Queue)
                Destination destination = session.createQueue("TEST.FOO");

                // Create a MessageConsumer from the Session to the Topic or Queue
                MessageConsumer consumer = session.createConsumer(destination);

                // Wait for a message
                Message message = consumer.receive(1000);

                if (message instanceof TextMessage) {
                    TextMessage textMessage = (TextMessage) message;
                    String text = textMessage.getText();
                    System.out.println("Received: " + text);
                } else {
                    System.out.println("Received: " + message);
                }

                consumer.close();
                session.close();
                connection.close();
            } catch (Exception e) {
                System.out.println("Caught: " + e);
                e.printStackTrace();
            }
        }

        public synchronized void onException(JMSException ex) {
            System.out.println("JMS Exception occured.  Shutting down client.");
        }
    }
}