This feature request is for supported, documented and proven way for disabling any user from calling JVM/JRE at all (alter system set java_user_access='off' or even better something similar to "revoke java_user_access from resource/connect/create session") - so even in SYS owned schemas JAVA objects are not being accessible for typical users in order to reduce the attack surface (this would increase security; see recent 2014/2015 OJVM security nightmare)