Starting with oracle hopefully.
(Un)fortunately (and IANAL) I don't think copyrights are enforceable if you don't enforce them everytime you know of a violation.
That won't happen because IBM also uses a lot of Java stuff including the great eclipse infrastructure. They will end up suing each other for a lot of components if that happens. If rumors are to be believed, Oracle and IBM have some sort of "agreement" that they won't sue each other on these matters.
I would venture a guess that IBM is a paid up licensee of Java, they've been releasing their own proprietary JVM for quite a while and never been sued by Sun/Oracle for it AFAIK