The types that are part of the Java platform are members of various packages that bundle classes by function: fundamental classes are injava.lang, classes for reading and writing (input and output) are injava.io, and so on. You can put your types in packages too. ...
As we mentioned before, Swing provides three generally useful top-level container classes: JFrame, JDialog, and JApplet. When using these classes, you should keep these facts in mind: To appear onscreen, every GUI component must be part of a containment hierarchy. A containment hierarchy is ...