Summary

In today's lesson, you learned about legacy and non-Java systems and how you can integrate J2EE applications with these. The lesson illustrated the J2EE Connector architecture, including the roles and contracts it defines. Building on this, you learned about the Common Client Interface and then wrote an application that utilized it.

The lesson continued by providing you with a high-level introduction to CORBA. You then learned how two Java technologies, Java IDL and RMI over IIOP, allow you to write CORBA objects and communicate with them. Finally, you learned how to use the Java Native Interface (JNI) to provide seamless interaction between Java applications and non-Java code, whether it was a lower-level language, a legacy library, or an application written in a non-Java programming language.

There were a lot of aspects to today's lesson, and this breadth meant that it wasn't possible to provide an absolutely complete reference to each of the technologies. However, the lesson has provided you with enough information on how and why you use these technologies for you to make an informed choice of which might best suit your particular application development requirements.