The following questions, I think would be good for a midterm:
1) What are the pros/cons of Code Review and Automated Code Assurance? Why do we need both?
2) What event would you need to override in order for your Robocode Robot to react appropriately to hitting a wall?
3) What is the main principle of The Principle of Least Astonishment (found in The Elements of Java Style)?
4) What feature was added to Java to make dealing with primitive data types easier?
5) What JUnit method would you use to test if an object is equal to its expected outcome?
Sounds pretty good if I could say myself.