Implementation of JMS interface methods

There are lot Interface methoods that which J2EE APIs provide. Ex: QueueConnectionFactory, QueueConnection, QueueSession by JMS.

I want to know, how and where the methods within these Interfaces are implemented? (ex: QueueConnectionFactory.createQueueConnection().)

Someone please assist me on this...

That's in the source code of JMS servers like OpenJMS, OpenMQ and ActiveMQ.

Thanks Dittmer for your response. Now I would like to go little more, please let me know if my understanding is correct.

Let us consider this example.

// The appserver connects to the the JMS provider/server using the jms configuration. Then the JMS server returns a QueueConnection, back to the Java client. ??
// Here appserver acts as an interface between the JMS client and server.
QueueConnectionFactory queueConnectionFactory = (QueueConnectionFactory) context.lookup("jms/SampleQCF");

//The appserver identifies the implementation for this method, on the JMS server and makes a call??
queueConnection = queueConnectionFactory.createQueueConnection();