While working on JBAS-1663, I noticed ejbRemove() is also not called for SLSBs that are "released" from the pool.. (This may be true for MDBs since they share the same pooling implementation).

E.g. with a MaxPoolSize of 100 that is not upper bound and 150 concurrent requests, the additional 50 session bean instances that will be temporarily created to handle the load, will not be ejbRemove()'d after they are returned to and released from the pool (the pool is already full so they are just left for GC).

Although the ejb spec is not very strict about ejbRemove() being called, there is not a good reason not to do so, in this case.

See org.jboss.test.session.test.EjbRemoveUnitTestCase