As we mentioned earlier, JMS is the Java standard API for implementing message-oriented middleware. Any typical Java EE application server (Glassfish, Wildfly, WebLogic, and so on) will have its own implementation for this API. In other words, you don't care, as a Java EE application developer, about the actual implementation used within an application server, and you will be focusing more on API concepts.
In the next section, we are going to discuss the architecture and the constituent parts of a typical JMS application.