Create an application, with a square window in the center of the screen that is half the height of the screen by deriving your own window class from JFrame.
Add a menu bar containing the items File, Edit, Window, and Help.
Add a pull-down menu for Edit containing the two groups of items of your own choice with a separator between them.
Add another item to the Edit pull-down menu which itself has a pull-down menu, and provide accelerators for the items in the menu.
Here's an exercise to tickle the brain cells – use a SpringLayout to obtain the button arrangement shown below in an application window.