Verify some properties of your implementation using Java PathFinder (JPF). Just running JPF on your code is not enough. Either you add something to your code that enables you to check a property. Or you consider minor variations on your implementation (showing, for example, that a particular lock is essential to guarantee deadlock freedom). Or you implement a listener that checks a particular property. Etcetera.

In your report, describe the properties you checked. Also explain how you checked them. Furthermore, report the results of your verification effort. Finally, draw some conclusions.