With the Extract Interface refactoring, you can create an interface that is based on the selected type. The Extract Interface dialog displays a list of methods and specifications that you can use to create new method specifications.
Extract an interface
Place the caret at a type, an interface, or a method that you want to use as a base for a new interface.
In the Extract Interface dialog, select members that you want to extract along with the interface.
Specify the extract location in To directory, To file, and To package fields.