Rod Johnson on portability of J2EE applications

Rod Johnson, the father of Spring, wrote in his famous book "Expert One-on-One J2EE Design and Development" (2002):

"Portability is a great bonus of the J2EE platform. <...> portability can be achieved in real applications, but it's not the point of J2EE. The requirement of the vast majority of projects is to build an application that solves a particular problem well on one target platform. An application that runs badly on one platform will never be ported to other platforms (the application might be ported to another operating system that runs on more powerful hardware to gain adequate performance, but that's not the kind of portability that professional developers aspire to).

J2EE orthodoxy holds that an application should be portable across J2EE application servers and must be able to work with different databases. The distinction between these two goals is important, and sometimes missed. Portability between application servers may deliver business value and is usually a realistic goal. Portability between databases is much more fraught, and often provides no business value.

Portability is usually taken to mean code portability: the ability to take the application and run it on another platform without any change. <...> this is an expensive misconception. Naïve emphasis on total code portability often leads to heavy costs in lost productivity and less satisfactory deliverables. Write Once Run Anywhere (WORA), while a reality where Java itself is concerned, is a dangerous slogan to apply to enterprise development, which depends on a range of resources.

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The portability myth has led to wide acceptance that J2EE applications can't use the capabilities of today's relational databases, but should use them only as dumb storage. This does great harm in the real world."