Of course they MUST be serializable or otherwise serialization will fail. you have ways to handle that by: 1.making variables transient 2.subclassing the class and making it implement serializable 3.overriding writeObject() . But you can't say that the phrase isn't true. Please tell me if you don't agree.
And did you try taking ExamLab mocks they are a bit harder to toughen you up for the real exam .
I am like you revising right now and getting ready to take the exam after a couple of weeks ,so we can share mock scores