This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
I guess the question comes from the point that, if DispatchAction does not have any abstract methods why do we mark it as abstract. Read the last comment of this similar discussion and I think it should answer your question.
He who asks a question is a fool for five minutes; he who does not ask a question remains a fool forever - Chinese proverb