No, that's not how open-source licensing usually works.
Assuming Oracle own all the IP rights (having purchased them from Sun), they aren't bound by the terms of the GPL. The GPL grants certain permissions to others if they comply with its terms, but the person who offers the license doesn't lose any rights they already have. They have no obligation to keep successive generations of derivative products open source.
True, that's even spelled out in the GPL itself (that's from GPL 2, but GPL 3 has similar content in section 9):
> 5. You are not required to accept this License, since you have not signed it. However, nothing else grants you permission to modify or distribute the Program or its derivative works. These actions are prohibited by law if you do not accept this License. Therefore, by modifying or distributing the Program (or any work based on the Program), you indicate your acceptance of this License [...]
The copyright owner obviously doesn't need the license to have permission to modify the code, so they're not bound by it.
Assuming Oracle own all the IP rights (having purchased them from Sun), they aren't bound by the terms of the GPL. The GPL grants certain permissions to others if they comply with its terms, but the person who offers the license doesn't lose any rights they already have. They have no obligation to keep successive generations of derivative products open source.