EVERY service company hasa certain level of interview while interviewing an experienced developer. If you are 2–4 yrs xp dev then the level would be fairly basic. But given the competition and availability of java devs in market it can go a little upwards to advanced level. Going by my experience when i was interviewed at 5 yrs xp it was strictly sticking to basics. Go with clarity of basic concepts like core java, polymorphism, inheritance, basic front end knowledge of js and jquery, threading, and knowledge of a certain java based framework like spring and knowledge about writing test cases. You would be good.
