Creation date: 14 March, 2011

Interface methods are always public

Look at the following code carefully and try to find the error:

package mypackage;
 interface MyInterface{
   void go();
 }

 public class B implements MyInterface{
   void go(){
     System.out.println("running method go()");
   }

   public static void main(String[] args) {
     B b = new B();
     b.go();
   }
 }

If you can't find the erroneous code, then remember, that all interface methods are implicitly public abstract. Hence if you implement the method your implementation must have public access modifier because you can not assign weaker access privileges than in interface. Your go() method must be look like so:

   public void go(){
     System.out.println("running method go()");
   }

Author: Jafar N.Aliyev (Jsoft)

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