Re: Java 8 question about default and static methods in interfaces

From:
Wayne <nospam@all.invalid>
Newsgroups:
comp.lang.java.programmer
Date:
Sun, 26 Jan 2014 20:37:00 -0500
Message-ID:
<0LiFu.157075$JL1.152266@fx08.iad>
On 1/26/2014 1:12 PM, Arne Vajh??j wrote:

On 1/26/2014 7:56 AM, Arne Vajh??j wrote:

On 1/26/2014 4:55 AM, Wayne wrote:

   public interface Foo {
     default void method () {
       System.out.println("Foo.method");
     }
   }
   public interface Bar extends Foo {
     default void method () {
       System.out.println("Bar.method");
     }
   }

The question is, can Foo.method be used from Bar.method?
In other words, is the following version of Bar legal?

   public interface Bar extends Foo {
     default void method () {
       super.method();
       System.out.println("Bar.method");
     }
   }


Well - the following compiles and run with Java 8 EA something:

public class DefMet {
     public static void main(String[] args) {
         Bar o = new C();
         o.method();
     }
}

class C implements Bar {
}

interface Foo {
     default void method () {
         System.out.println("Foo.method");
     }
}

interface Bar extends Foo {
     default void method () {
         Foo.super.method();
         System.out.println("Bar.method");
     }
}

Note the use of Foo.super instead of just super.


Syntax must be intended for:

public class DefMet2 {
    public static void main(String[] args) {
        Bar o = new C();
        o.method();
    }
}

class C implements Foo, Bar {
    public void method() {
        Foo.super.method();
        Bar.super.method();
        System.out.println("C.method");
    }
}

interface Foo {
    default void method () {
        System.out.println("Foo.method");
    }
}

interface Bar {
    default void method () {
        System.out.println("Bar.method");
    }
}

Arne


Thanks!

--
Wayne

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