Hi folks, We have a hang between LdapClient / Ctx due to the fact that Connection.cleanup() calls LdapClient.processConnectionClosure which locks the unsolicited vector and in turn calls LdapCtx.fireUnsolicited which locks the eventSupport object. Unfortunately when an LdapCtx.close() occurs at the same time, its removeUnsolicited method locks the eventSupport object first and then attempts to call LdapClient.removeUnsolicited which attempts to lock the unsolicited vector. So: thread 1: Connection.cleanup -> LdapClient.processConnectionClosure (LOCK VECTOR) -> LdapCtx.fireUnsolicited (LOCK EVENTSUPPORT) (LdapClient is looping through LdapCtx objects in the unsolicited vector) thread 2: LdapCtx.close (LOCK LDAPCTX) -> LdapCtx.removeUnsolicited (LOCK EVENTSUPPORT) -> LdapClient.removeUnsolicited (LOCK VECTOR) (A single LdapCtx removes itself from its LdapClient unsolicited list) My proposed solution is to have both threads lock the LdapClient before locking either the unsolicited vector or the eventSupport object. Webrev at: http://cr.openjdk.java.net/~robm/8129957/webrev.01/ -Rob