What are the concepts to master after completing beginer,advanced java?

Question

Whether to focus on ds or projects?

Answer 1

After completing it please have a look on Java 8 and Java 9 ,modularity!! Go to the documentation and explore deep and more! After that it's your choice whether wanna start Hibernate, Spring for Android etc!!

Answer 2

If I were you I'd probably go and learn mobile app development (Android). But if you're that much into DS then of course choice is yours.