defaultButton
Makes this button the default button of the window it is in - the one the look and feel's activation keystroke, Enter in the look and feels the JDK ships, activates wherever the focus sits, as long as the button is an enabled descendant of the root pane at that moment. A component that consumes the activation event itself, a text pane among them, keeps it. The association follows the button when it moves to another window, and is released when default is false or the modifier leaves. Requires a JButton target.
Return
this chain with the default-button association declared on it.
Parameters
default
whether this button is the window's default button.