Java_Interface

Interface.java

//fields are implicitly : public  & static & final.
//methods are implicitly : public & abstract.
//since fields are abstract interface doesn't support constructor.
//>>class C2 extends C1 implements I3<<
//Above syntax also possible.

interface I1{
    void f1();
}
interface I2{
    void f2();
}
interface I3 extends I1,I2{
    void f3();
}
abstract class C1 implements I3{
    abstract void f4();
}
class C2 extends C1{
    public void f5(){
        System.out.println("From C2");
    }
    public void f1(){
        System.out.println("From I1");
    }
    public void f2(){
        System.out.println("From I2");
    }
    public void f3(){
        System.out.println("From I3");
    }
    public void f4(){
        System.out.println("From C1");
    }
}
class Interface{
    public static void main(String[] a){
        C2 obj = new C2();
        obj.f1();
        obj.f2();
        obj.f3();
        obj.f4();
        obj.f5();
    }
}