Cast a class that is dynamically obtained

Question

I am trying to cast a class that I dynamically obtain that has implemented an interface. I have tried the following below but it doesn't seem to work. How I achieve this.

public InterfaceX test(){

 InterfaceX x = null;
 Class<?> classX = Class.forName("com.TestClassX");
 x = (InterfaceX) classX;
 return  x;

}

EDIT: I dont want to create an instance, since I am just looking to simply call a static method defined by the interface.

Answer 1

If x is a Class object, you cannot do x.staticMethod(). However, this is possible using reflection.

public interface Interface {
    static void method() {
        System.out.println("Hello, World!");
    }
}

Then, in the main class you can do this.

import java.lang.reflect.*;

public class Main  {

    public static void invokeMethod(String className)  {
        try {
            Class<?> clazz = Class.forName(className);
            Method method = clazz.getDeclaredMethod("method");
            method.invoke(null);   // null is used for static methods. For instance methods, pass the instance.
        } catch (ClassNotFoundException | NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        invokeMethod("Interface");
    }
}

This works, but you should generally try to avoid using reflection (anything in java.lang.reflect). Most of the time there is a better solution to the problem you are trying to solve.