What does Java EE compliant means?

Question

We often say that the particular application server is a Java EE compliant server. But I am still not completely aware of what it means exactly. Need more information on this.

Answer 1

It means that it passes the Java EE Technology Compatibility Kit.

Sun (now Oracle) created the specification for Java EE (previously called J2EE) along with a large test suite checking that the application server behaves as the specification requires. This is a non-trivial test to pass, but means that if you write your application according to the Java EE specification it will be able to be deployed and executed on any Java EE application server (of that level).

Note that the configuration is outside the specification. This means that the configuration of the application server to provide the things your application needs, is non-standard and it may be a quite substantial effort for you to add support for a new application server.