What is meant by user defined method, class and predefined method , class ?

What is meant by user defined method, class and predefined method , class ?

What is meant by user defined method and predefined method?

Developer defined method is called user defined or custom method.already defined methods are called predefined methods  .these methods may be developed by sun microsystem developers or ,some other developers .

example-println() method is predefined

What is meant by user defined class and predefined class ?

Developer defined class is called user defined or , custom class.already defined class is called predefined class .these class may be developed by SUN Microsystem developers , or some other developers .

For example-System , String           are predefined classes

                       

                     First Program , A,B       are user defined classes