Question

Say I have the following:

public class A {
  //stuff
  public class B implements I {}
}

public interface I {}

public class Foo {
  int bar(I i) {}
}

Now why does Java give me a build error of ‘not applicable for type…’ when I try to pass an instance of B to Foo.bar() inside the body of class A?

Is the inner class not considered a proper implementation of I because it is contained inside a top-level class?

Cheers, Dave.

Answer 1

You need a Instance of class A, before you can create a instance of object B (because B is a inner class of A).
Try this code:

Foo foo = new Foo();
A a = new A();
B b = a.new B();
foo.bar(b);