3.4 Summary
Key points to remember:
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Transaction Component Middleware (TCM) is the dominant technology today for transaction processing applications. The two leading TCMs are Enterprise JavaBeans (EJB) and .NET Enterprise Services (formerly COM+).
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These two dominant TCM technologies both use OO interfaces. OO interfaces have greater flexibility than older interface styles like RPC and fit well with OO programming languages. But there is a cost in greater complexity because there are objects to be referenced and managed.
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TCMs are preferable to older OO middleware styles like DCOM and CORBA because developing transactional applications is easier (there is much less to do) and the software provides object and database connection pooling, which improves performance.
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Web browsers are significantly different from older GUI applications or green-screen terminals. The browser user has more control over navigation, the server can make far fewer assumptions on the nature of the device, and session handling is different. In particular, the Web application server has no idea when the browser user has finished using the application.
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While there are many fancy features for session handling in EJBs, a simple approach using stateless sessions is usually best. The old adage, KISSKeep it Simple, Stupidapplies.
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In large organizations, the chances are you will have to work with both .NET and Java for the foreseeable future.