How can I get the implementation class name based on the interface object in Java

Question

I want to get the implementation class name from my interface object — is there any way to do this?

I know I can use instanceof to check the implementation object, but in my application there are nearly 20 to 30 classes implementing the same interface to override one particular method.

I want to figure out which particular method it is going to call.

Answer 1

Just use object.getClass() - it will return the runtime class used implementing your interface:

public class Test {

  public interface MyInterface { }
  static class AClass implements MyInterface { }

  public static void main(String[] args) {
      MyInterface object = new AClass();
      System.out.println(object.getClass());
  }
}