Java is an object-oriented programming language which means you can use Java to develop your programs in terms of data and the methods (functions) that operate on the data. In Java, a class is a COLLECTION of the data and methods which describe an object with which your program works. Think of an object as a "THING," such as a graphics IMAGE, a dialog box, or a file.
Java APPLETS can ARRANGE classes in hierarchical fashion which means you can build new classes from existing classes, improving upon or extending the existing class's capabilities. Everything in Java, except for a few primitive types such as numbers, characters, and boolean (true and false) types, is an object. Java comes with an extensive set of classes that you can use in your programs. In fact, a Java applet itself is a Java class.

Java is an object-oriented programming language which means you can use Java to develop your programs in terms of data and the methods (functions) that operate on the data. In Java, a class is a collection of the data and methods which describe an object with which your program works. Think of an object as a "thing," such as a graphics image, a dialog box, or a file.
Java applets can arrange classes in hierarchical fashion which means you can build new classes from existing classes, improving upon or extending the existing class's capabilities. Everything in Java, except for a few primitive types such as numbers, characters, and boolean (true and false) types, is an object. Java comes with an extensive set of classes that you can use in your programs. In fact, a Java applet itself is a Java class.