Each version of the Java EE platform must be able to run on the associated version of the Java SE platform. So, J2EE 1.4 must be able to run on J2SE 1.4 , Java EE 5 must be able to run on Java SE 5, etc.Note that this doesn't mean a particular implementation of Java EE can't be run with a more recent version of the JDK. For example, the J2EE 1.4 SDK can be run with J2SE 1.4 or Java SE 5.The key is that both the implementation of the Java EE platform and the applications written to that particular release of the platform must write to the corresponding Java SE version API.In other words, neither a J2EE 1.4 implementation nor a J2EE 1.4 application should make use of an API that was *added* in Java SE 5.
--ken