Migrating J2EE-compliant applications

The principal benefit of developing an application to the J2EE standard is to ensure its portability between any of the application servers that pass the compatibility tests devised by Sun Microsystems. 

So that’s the theory, what about the reality?

As an exercise for one of Maddox Ford’s clients – users of both SilverStream and Oracle 9i AS – we attempted to migrate a J2EE-compliant application developed by us in SilverStream to run under Oracle 9i AS.

And the result? Migration at the first attempt with no problems.

Essentially the migration involved a drag and drop manoeuvre from one directory to another. Oracle unpacks the application’s WAR file and automatically creates the directory structure specified in the WAR. In SilverStream. deployment descriptors (proprietary XML files containing information such as resource references and servlet initiation parameters) are needed to successfully deploy to the application server. In Oracle 9i AS, however, these are not always needed - again aiding the ease of deployment. To bind a new application to Oracle 9i AS, all that is required is the configuration of a few XML files. Once achieved, the application is up and running!