I coded a Mancala game in Java for a college class this past spring, and I used the Eclipse IDE to write it. One of the great (and fairly simple) visual aids in Eclipse is
The highlight functionality is conveniently implemented in VisualAssist. In my opinion, they are both must-have.
1) Highlight identifier under editing caret: Options -> Advanced -> Refactoring -> Automatically highlight references to symbol under cursor
2) Highlight search result - in all windows. Works for RegExps! Options -> Advanced -> Display -> Highlight find results