The "contentPane" is the primary container for application specific components. Applications should add children to the contentPane, set its layout manager, and so on.

The contentPane may not be null.

Generally implemented with getRootPane().setContentPane(contentPane);

Parameters:

contentPane the Container to use for the contents of this JRootPane

Exceptions:

java.awt.IllegalComponentStateException (a runtime exception) if the content pane parameter is null