Best thing to do is find a tough problem and solve. Most of what you'll encounter in the workplace is new territory, so know the basics, know how to locate and search through API's and get good at logic. Logic problems will help you more than anything (in my opinion), because like I said, the workplace is completely new territory and it's nearly impossible to study for the things they'll have you doing.

Hi,
I think the best way to gain experience in any coding langauge is to get stuck in their and figure it all out, try a get a piece of java software or what have you and go about dismantling it and re-coding it.