Collections and Generics

Abstract

Everything in Java is an object. As you learned in Chapter 9, you can even make the primitive values act like objects by wrapping them in the wrapper classes. The wrapping and unwrapping of primitive values, which is also called boxing and unboxing, has been automated in J2SE 5.0 and is called autoboxing. So, you can assume that all the data types in Java can be treated like objects of classes. All the objects in Java share some methods, which they inherit from the Object class at the root of the Java class hierarchy—that is, it is a superclass of all classes in Java.