This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
Java.io - all constructors and the bulk of the methods Java.lang - String, StringBuffer Java.util - All the interfaces and the major classes and bulk methods, ie Hashtable, Vector, etc. Those are off the top of my head.