Section 23.5. Abstracting Legacy Applications

23.5. Abstracting Legacy Applications

One of the best uses of J2EE technology, particularly the EJB technology, is to provide a single common interface to heterogenous systems. If an application provides any sort of file, data, pipe, or network access to its data, you can wrap an EJB interface around it and make it available to an entire distributed network. This can be a powerful way to leverage investments in legacy systems with modern multitier architectures.

While it is commonplace for EJB applications to interface directly to a relational database back end, there is no requirement that such a system be the back end. IBM, for example, provides Java interfaces to their mainframe legacy data systems, such as CICS.