Why can't java find my method?

Question

I am trying to wrap my mind around something in java. When I pass an object to another class' method, can I not just call any methods inherent to that object class?

What is the reason code such as the example below does not compile?

Thank you,

class a {
  public static void myMethod(Object myObj) {
    myObj.testing();
  }
}


class b {
  public void testing() {
    System.out.println ("TESTING!!!");
  }
}


class c {  
  public static void main (String[] args) {
    b myB = new b();    
    a.myMethod(myB);  
  }
}

Edit: The reason I have left the parameter in myMethod as type Object, is because I would like to be able to pass in a variety of object types, each having a testing() method.

Answer 1

If you would like to pass in a variety of objects with testing() methods, have each object implement a Testable interface:

public interface Testable
{
   public void testing()
}

Then have myMethod() take a Testable.

public static void myMethod(Testable testable)
{
  testable.testing();
}

---

Edit: To clarify, implementing an interface means that the class is guaranteed to have the method, but the method can do whatever it wants. So I could have two classes whose testing() methods do different things.

public class AClass implements Testable
{
   public void testing()
   {
      System.out.println("Hello world");
   }
}

public class BClass implements Testable
{
   public void testing()
   {
      System.out.println("Hello underworld");
   }
}