Hopefully my Introduction to Applets will help you get started with Java programming. I learned Java from Java in a Nutshell, 2nd. Exploring Java, Java Fundamental Classes Reference, The Abstract Window Toolkit, and the Java Language Reference. In Java, even your program is an object. Just about everything in Java is considered an object.
Objects are instances of a class.
Another is inheritance . The new class is a descendant, or subclass , of the old class. Consequently, the old class is a superclass of the new class. In the case of applets, inheritance plays a major role in that all applets are subclasses of the Applet class- and Applet itself is an abstract class. You can't do this in Java, because Java's creators felt that it was very hard to use multiple inheritance without creating messy, complicated code.