Yes, you can. The copyright owner always has that right...which is why Oracle now requires all contributors to assign joint copyright ownership of their code to

Yes, you can. The copyright owner always has that right...which is why Oracle now requires all contributors to assign joint copyright ownership of their code to Oracle. In fact, the only reason you would need copyright ownership of contributor code is to reserve the right to change the licensing. Oracle wanted to do it with MySQL, but their lack of copyright ownership for some parts of a GPL-ed MySQL codebase made it impossible. They fixed that mistake with their new contributor agreement, ensuring that they always have control over your code if you contribute.