Suppose you want to create one form to be a base (superclass) for other forms (extending the base one). You can create the base form as usual, but it should match the requirements described in Creating a custom container bean:

To create a form extending the base form, use Bean Form template and set its superclass to the base form class.

Some additional notes:

Tip for iterative development:

If you change something in the base form, don't forget to compile it. If there are some extending forms opened at the same time, they won't be updated automatically -- you must reopen them to load the new base class (to do it quickly, press Ctrl+R in each form).

Source: NetBeans User FAQ

Parent Category: Other API Tips