The Programmer's Guide contains information on how to use the ORB Portability Layer. Although the CORBA specification is a standard, it is written in such a way that allows for a wide variety of implementations. Unless writing extremely simple applications, differences between ORB implementations tend to produce code which cannot easily be moved between ORBs. This is especially true for server-side code, which suffers from the widest variation between ORBs. There have also been a number of revisions of the Java language mapping for IDL and for CORBA itself. Many ORBs currently in use support different versions of CORBA and/or the Java language mapping.

The JBossJTS only supports the new Portable Object Adapter (POA) architecture described in the CORBA 2.3 specification as a replacement for the Basic Object Adapter (BOA). Unlike the BOA, which was weakly specified and led to a number of different (and often conflicting) implementations, the POA was deliberately designed to reduce the differences between ORB implementations, and thus minimize the amount of re-coding that would need to be done when porting applications from one ORB to another. However, there is still scope for slight differences between ORB implementations, notably in the area of threading. Note, instead of talking about the POA, this manual will consider the Object Adapter (OA).

Because the JBossJTS must be able to run on a number of different ORBs, we have developed an ORB portability interface which allows entire applications to be moved between ORBs with little or no modifications. This portability interface is available to the application programmer in the form of several Java classes. Note, the classes to be described in this document are located in the com.arjuna.orbportability package.