Building Your Own Classes

• Building a program normally requires a number of classes.
• One must have the public static void main(String args[]) method, often simply called a main method.  This is the one that starts the entire program.
• Others need not have a main method, but often do for unit testing purposes.
• Nearly all classes have instance fields and methods.  I'd have a hard time thinking of a class that wouldn't.
• All classes require constructors.
• If you do not have a constructor or cannot afford one, Java will provide one for you.
• This is called the default constructor, it takes no arguments (parameters).
• You can have parameters in a constructor if you specify them.  If you do this, or if you simply make one without parameters, Java will not create the default constructor.


 Take a look at the previous example
 Constructors

Created by:  Brandan Jones January 4, 2002
Updated February 25, 2003