Body The body of the interface contains method declarations . The method declaration is terminated by a semicolon and no body is provided for the method. You may not use transient , volatile , private , protected , or synchronized in a member declaration in an interface. All methods declared in an interface are implicitly public and abstract . The body of the interface may also define constants.
Constant values defined in an interface are implicitly public , static , and final .
The interface extended interfaceX and interfaceY . Implementing an Interface You use an interface by defining a class that implements the interface by name. When a class claims to implement an interface, it must provide a full definition for all the methods declared in the interface as well as all of the methods declared in all of the superinterfaces of that interface. A class can implement more than one interface by including several interface names in a comma-separated list of interface names. In that case, the class must provide a full definition for all of the methods declared in all of the interfaces listed as well as all of the superinterfaces of those interfaces.