How is the implements keyword different from extends?
The implements keyword is used when a class explicitly fulfils an interface definition with concrete method implementations for its abstract method signatures. A single class can implement more than one interface, but must be declared abstract if it does not implement all interface methods. The extends keyword is used when an interface inherits the type definition specified in a super-interface, or a class inherits from a superclass. A class can only extend a single superclass but may also implement one or more interfaces. When an interface extends a super-interface it is not required or permitted to implement any of its abstract methods since the sub-interface must be abstract itself. Actions: Follow-up or correct this answer. Submit a new question.
