javaoopextendsimplements

extends class and implements interface in java

interface Bouncable{ } 
interface Colorable extends Bouncable{ } 
class Super implements Colorable{ } 
class Sub extends Super implements Colorable {} // Ok (case -1)

But,

class Sub implements Colorable extends Super {} // error (case -2)

Why case-2 showing compilation error { expected. Why ?? Although, case-1 executes without error.

Solution

  • extends should go before implements:

    class Sub extends Super implements Colorable {}