Why is an inner class forced to implement its interface methods, even if the outer class has it?

Question

public class Outer{
  public void sayHello(){ System.out.println("Hello!");}
  public class Inner implements HelloSayers{}
public interface HelloSayers{
  public void sayHello();
}

The type Outer.Inner must implement the inherited abstract method HelloSayers.sayHello().

But the problem is the inner class should be considered as implementer of the outer methods. Am I wrong?

Answer 1

Yes, you are wrong.

Inner can access the members of Outer , but that does not mean it shares those members.

Ie every instance of Inner contains a reference to the corresponding Outer object ( Outer.this ). If you access a member of Outer from Inner in your java code, the compiler just translates this to a access to the member of the Outer referenced by the Inner object. The Inner class does not contain those members.