ActiveMQ and embedded broker

Question

EDIT: Rephrased the question:

I want to use ActiveMQ as a messenger service between my server and client applications.

I am trying to set up an embedded broker (i.e. not a separate process) within the server to handle the produced messages for my clients to consume. This queue is persisted.

The broker initialisation as follows:

BrokerService broker = new BrokerService();
KahaPersistenceAdapter adaptor = new KahaPersistenceAdapter();
adaptor.setDirectory(new File("activemq"));
broker.setPersistenceAdapter(adaptor);
broker.setUseJmx(true);
broker.addConnector("tcp://localhost:61616");
broker.start();

After tinkering, I ended up with the server part being:

public static class HelloWorldProducer implements Runnable {
    public void run() {
        try {
            ActiveMQConnectionFactory connectionFactory = new ActiveMQConnectionFactory("tcp://localhost"); // apparently the vm part is all i need
            Connection connection = connectionFactory.createConnection(); 
            connection.start();
            Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
            Destination destination = session.createQueue("TEST.FOO");
            MessageProducer producer = session.createProducer(destination);
            producer.setDeliveryMode(DeliveryMode.NON_PERSISTENT);
            String text = "Hello world! From: " + Thread.currentThread().getName() + " : " + this.hashCode();
            TextMessage message = session.createTextMessage(text);
            System.out.println("Sent message: "+ message.hashCode() + " : " + Thread.currentThread().getName());
            producer.send(message);
            session.close();
            connection.close();
        }
        catch (Exception e) {
            System.out.println("Caught: " + e);
            e.printStackTrace();
        }
    }
}

The client is very similar and looks like this:

public static class HelloWorldConsumer implements Runnable, ExceptionListener {
    public void run() {
        try {
          ActiveMQConnectionFactory connectionFactory = new ActiveMQConnectionFactory("tcp://localhost");
            Connection connection = connectionFactory.createConnection(); // exception happens here...
            connection.start();
            connection.setExceptionListener(this);
            Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
            Destination destination = session.createQueue("TEST.FOO");
            MessageConsumer consumer = session.createConsumer(destination);
            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 obj: " + message);
            }
            consumer.close();
            session.close();
            connection.close();
        } catch (Exception e) {
            System.out.println("Caught: " + e);
            e.printStackTrace();
        }
    }

The main method simply starts each of these in a thread to start producing/receiving messages.

...but I am running into the following with the start of each thread:

2013-01-24 07:54:31,271 INFO  [org.apache.activemq.broker.BrokerService] Using Persistence Adapter: AMQPersistenceAdapter(activemq-data/localhost)
2013-01-24 07:54:31,281 INFO  [org.apache.activemq.store.amq.AMQPersistenceAdapter] AMQStore starting using directory: activemq-data/localhost
2013-01-24 07:54:31,302 INFO  [org.apache.activemq.kaha.impl.KahaStore] Kaha Store using data directory activemq-data/localhost/kr-store/state
2013-01-24 07:54:31,339 INFO  [org.apache.activemq.store.amq.AMQPersistenceAdapter] Active data files: []
2013-01-24 07:54:31,445 DEBUG [org.apache.activemq.broker.jmx.ManagementContext] Probably not using JRE 1.4: mx4j.tools.naming.NamingService
2013-01-24 07:54:31,450 DEBUG [org.apache.activemq.broker.jmx.ManagementContext] Failed to create local registry
    java.rmi.server.ExportException: internal error: ObjID already in use
    at sun.rmi.transport.ObjectTable.putTarget(ObjectTable.java:186)
    at sun.rmi.transport.Transport.exportObject(Transport.java:92)
    at sun.rmi.transport.tcp.TCPTransport.exportObject(TCPTransport.java:247)
    at sun.rmi.transport.tcp.TCPEndpoint.exportObject(TCPEndpoint.java:411)
    at sun.rmi.transport.LiveRef.exportObject(LiveRef.java:147)
        <snip....>

It seems like the messages are produced and consumed successfully (the other issues I previously posted about was resolved), but the above exception is worrying me.

EDIT: During broker shutdown, I am now also greeted by the following:

2013-01-25 08:40:17,486 DEBUG [org.apache.activemq.transport.failover.FailoverTransport] Transport failed with the following exception:
    java.io.EOFException
    at java.io.DataInputStream.readInt(DataInputStream.java:392)
    at org.apache.activemq.openwire.OpenWireFormat.unmarshal(OpenWireFormat.java:269)
    at org.apache.activemq.transport.tcp.TcpTransport.readCommand(TcpTransport.java:210)
    at org.apache.activemq.transport.tcp.TcpTransport.doRun(TcpTransport.java:202)
    at org.apache.activemq.transport.tcp.TcpTransport.run(TcpTransport.java:185)
    at java.lang.Thread.run(Thread.java:722)

Answer 1

You can embed a broker into your code in a number of ways, much of which is documented here. You may want to try upgrading you version since what you are using appears to be quite old as it defaulting to the now deprecated AMQ Store instead of the newer KahaDB store. You might be having issues because of a race between the client threads as they use the different connection factories which could race to create in VM brokers. If you set the create=false option on the producer and ensure the consumer thread starts after that could address the issue, or you could create the VM broker ahead of time and the add create=false to both thread's and that might do the trick.

BrokerService broker = new BrokerService();
// configure the broker
broker.setBrokerName("localhost");
broker.setUseJmx(false);
broker.start();

And then in the client code just attach via this connection factory configuration.

ActiveMQConnectionFactory cf = new ActiveMQConnectionFactory("vm://localhost?create=false");