This web page has links to test questions which test the knowledge you gained from completing the Java Projects. Currently I'm not using any special testing technology. I'm using these test questions as a question bank to pull from for ILT (Instructor Lead Training) tests.
The best way to find out the answers to the test questions (and to learn) is to revisit the project and change the source code so as to prove what the correct answer should be.
Enjoy learning by example. Get your hands dirty in the source code!