Javaで、実行中にクラスを再読み込みする

public interface I {
  public void test();
}

public class A implements  I {
  
  public void test(){
    System.out.println("test1");
  }
}

public class A implements I {
  public void test(){
    System.out.println("test2");
  }
}

import java.io.*;
import java.net.*;

public class test {
  public static void main(String[] args){
    try {
      
      URLClassLoader cl = new URLClassLoader(new URL[]{new File("class1").toURI().toURL()});
      ((I)cl.loadClass("A").newInstance()).test();
      
      cl = new URLClassLoader(new URL[]{new File("class2").toURI().toURL()});
      ((I)cl.loadClass("A").newInstance()).test();
      
      // ((URLClassLoader)ClassLoader.getSystemClassLoader()).addURL(new File("class1").toURI().toURL());
    } catch (Exception e){
      System.out.println(e);
    }
  }
}