The recurring question was: how big is the jar needed for compiling / unit test of the EJB 3 pojos? The preview of EJB 3.1 distributed with Glassfish prelude v3 (javax.ejb-10.0-SNAPSHOT.jar) is: 42.2 KB (not MB). It contains most of the EJB 3.1 annotations. In most applications only the "mainstream" annotations are used - so the size of the jar can be further optimized to few KBs...