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.
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I'm not sure what the context of your question is. Depending on how fine you want to go, the J2EE API would be a good place to start, but depending on how the question is phrased it may also include JSPs as a technology separate to Servlets.