They can change it at their will and they can force all current implementations to update or lose their license. If Java was a standard as TCP/IP, then yes I'd agree, but JAVA=Vendor Lock-in just as much as Windows does.
Psssst . . .
Look it up. You won't believe me, so I won't even try.
Java *is* a standard. Sun does *not* control it. The 'Java Community Process' does.