When it comes to specific class use, the API specs
are your best friend. Java is extremely well-documented, given that you know what you're looking for. I linked to the Java 1.5 documentation, but you can replace the 1.5.0 in the url with whatever version you're using (ie. 1.4.2).
What's with all the <E> and <T> stuff in the Collections framework now? I couldn't help but notice that ArrayList.get(int index) now returns something with a class of E and ArrayList.add() takes an argument of class E. Also, ArrayList.toArray() returns an array of objects with class T