I've searched in ggl and found examples for Jdeveloper 11, and you can right-click on entities and press "synchronize", but in Jdeveloper 12c I can't see this option, I need to configure something or there's another way to do this in 12c?
If you are talking about Oracle ADF Business Components Entity Objects - than the synchronization menu option is still there in 12. JDeveloper never had a synchronize with DB option for JPA entities.