Why can I run the JMS API sample programs using the J2EE 1.2.x SDK?
The J2EE 1.2.x Reference Implementation did not include an implementation of the JMS API. It included only the interfaces. The JMS Reference Implementation is available as part of J2EE 1.3 and you can run the sample programs with the J2EE 1.3 server. See the JMS Tutorial for information on running simple JMS client programs with the J2EE 1.3 server.