In this chapter, we will expand on your knowledge of Java applications by showing how to instantiate (create) an object and demonstrating how constructors work. We will highlight the key differences between running a Java class as an application and creating an object. We will also provide a more detailed explanation of how Java “works” and “what comes with” Java. This explanation will also cover what really happened when you clicked buttons and chose RAD (Rational Application Developer) options in the previous chapter. In addition, we will explore some online documentation that explains the classes that “come with” Java.