keywords-extends

Use this keyword to list the base classes your class derives from. Omit the clause if Object is the only class you need to derive from. Classes can derive from other classes, structures, and primitives. Structures can derive from primitives and other structures. See the sections on [Classes], [Structures], and [Derivation] more information.

[(\abstract\ | \static\)] \class\ identifier
    [extends baseClassList]
    [implements interfaceList]