1. Review Java OO principles, specifically the idea that all Java classes are subclasses of the Object class, and thus must have all the methods of the Object class even if they don't show up in the Java code for the class. See S&W page 101. You can see the Object class API (and any other standard class) by following the link "JDK API" on the class web page under Resources. Choose Object in the pane titled All Classes, and the API will be displayed on the right.

   1. What are the four most important Object methods? (Hint: their names start with e, h, g, and t). Because all objects have these methods, we can use HashSet to contain almost any set of objects (but we'll stick to sets of similar-type objects in our work).
   2. Show equals in use by writing one if () that checks whether s String s is equal to a String t, character by character. Explain what this comparison is doing if s = abc and t = abx. Compare this to what happens in if (s == t).
   3. Find the hashCode and toString values for String s = xyz. Also for the Integer of value 8.