288

Conclusion

the old service interface but re implement the existing endpoint to use the new

implementation of the service. You may even be able to publish the new endpoint

under the same URL without breaking the existing clients. For example, if you are

just adding some additional ports to your WSDL, you should be able to update the

old WSDL with the new WSDL description and then existing clients should con 

tinue to work with no problems.

6.5.6 Writing Applications for Integration

One area in which you have quite a bit of flexibility involves how you code your

new EAI application. Since the application is new, you have the maximum amount

of choice for implementing how the application will access the various resources

that it requires. The J2EE platform, which is moving in this direction, provides some

facilities to help with this task.

The Java Business Integration (JBI) Systems Programming Interface, based

on JSR 208, extends the J2EE platform with a pluggable integration infrastructure

using WSDL based message exchange. JBI is of most interest to integration 

independent software vendors (ISVs) rather than enterprise developers. JBI

enables ISVs to write integration modules that support business protocols, such as

Business Process Execution Language (BPEL), and plug them into a J2EE appli 

cation server using JBI mechanisms. JBI also provides these integration modules

with useful services such as threading, context management, security, lifecycle

management, connection pooling, timers, and so forth. As a developer, you deal

with the Web services for the various JBI based integration services provided by

these ISVs.

6.6

Conclusion

This chapter examined some of the key issues for .

It began by illustrating typical integration problems encountered by enterprises, and

then described the various integration technologies available with the J2EE 1.4 plat 

form. These J2EE technologies are not limited to Web services only, though Web

services represent one valid integration approach most useful in certain situations. In

addition to Web services, the J2EE platform has technologies for integrating with

relational databases and other types of data stores, messaging technologies, and EIS

access technologies. 

The chapter described the major J2EE application integration approaches 

including using Web services, enterprise beans and JMS, connectors, and data