Java is an object-oriented programming language. To execute a Java program on the Java virtual machine, the JVM provides support for a number of basic object-oriented programming constructs. In this chapter we will explore that part of the JVM instruction set that facilitates an object-oriented programming style.
An object is an entity with four properties:
It has an identity. An object is not the same object as any other object.
It has a class. Each object is a member of exactly one class.
It may have fields. A field is a slot for storing values. All objects of the same class have the same fields. When you alter the fields of an object, it does not affect any other object.
It may have methods invoked ...