While you are developing your visual class, you can run it to see its appearance and behavior.
When you run a Java bean or application using the visual editor, a virtual machine is created that uses the class path specified in the Java Build Path of the project. The Java bean is then instantiated using its null constructor. If the Java bean is a visual class (is a subclass of java.awt.Component), an appropriate window is created to host the visual Java bean. If the bean is part of or inherits from an AWT Java bean, the window is a java.awt.Dialog. If the bean is a Swing class or inherits from a Swing class, the window is a javax.swing.JDialog. If the bean is an SWT class, the window is an SWT Shell. If the visual Java bean does not require a window because it itself is one, the Java bean will be made visible and given a default size after it has been instantiated.
When you run a class as a Java bean or application, a launch configuration is automatically created. The launch configuration is used to start a virtual machine that instantiates the class and allows it to be tested. If a launch configuration already exists for the class you are running, that launch configuration will be used.
To run a visual class as a Java bean or application: