Simple example in interface

Answer 1

Any device or construct that allows a human being to interact with a machine is an interface. The steering wheel of a car is an interface, the play button on a DVD video player is an interface, the close icon on a window is an interface, the CTRL+C accelerator is an interface, and so on.

Answer 2

Interfaces are extremely useful in creating inheritance hierarchies in java programs. Interfaces cannot be extended but they will be implemented.

Ex:

public Interface Interface1 {

public String getName() {};

}

public Interface Interface2 {

public int getAge() {};

}

public class InterfaceExample implements Interface1, Interface2 {

public String getName() {

return "Anand";

}

public int getAge() {

return 28;

}

}

Here I have implemented two interfaces in a class. I must provideimplementation for all the methods that are declared inside both interfaces. So for simplicity I have just written 1 method in each interface but in practical situations you may have numerous methods inside each interface.