Java: use instanceof with static inner class from different class

Question

public class A {
    static class B {
    }
}

public class C {
   void m(X x) {
      if (x instanceof A.B) { ... } // not working
   }
}

Is there a way to verify if some object (x) is actually the inner class (B) of some class (A) in this scenario?

I'm getting this error, but I unfortunately have no control over the classes A and B.

The type A.B is not visible

Answer 1

I made this answer as a comment, but with a little reflection (the thinking kind, not the coding kind!), I'm turning it into an answer.

Since you don't have control over A or B, and B has package access, you can only see it from classes that are in the same package as A. So what you could do - if you don't want to move C into the same package - is write a utility class - call it U - that has a boolean function, taking an X and returning whether it's an instance of A.B.

Answer 2

You can do like this.Both class A,C and Z resides in same package.

public class A { 

    static class B 
    { 
    } 
} 

    public class C {

        static void  m(Z x) { 

            System.out.println( x.getClass() + "^^^" +new A.B().getClass() );
            **if (x.getClass().equals(new A.B().getClass()))** 
              { 

              }
              // not working 
        } 


        public static void main(String[] args)
        {
            Z x = new Z(); 
             m(x);
        }
    }

    class Z
    {


    }