Hi Ramakrishnan,
what do you mean by "desktop java"?
Java classes are organized into packages, which belong together in some way. The core classes are packaged in the java.* pages. The most important ones are the java.lang package (e.g. Object,
String), the java.io package, and the java.util package.
Java contains an Abstract Windowing Toolkit (AWT) for creating basic graphical user interfaces (GUIs). The classes for implementing AWT-based GUIs are contained in the java.awt package.
However, AWT has only a limited scope. This is the reason why Swing has been developed for creating desktop applications. The Swing classes can be found in the javax.swing package (javax means "Java extensions").
Does this answer your question?