Test for URLClassLoader.close

Main.java

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLClassLoader;

public class Main {

  
  // Usage: run this class. It will block, waiting for input. Enter any string ("end" to exit).
  // Each iteration calls Test.printMe, which prints a message to standard out.
  // If the calls to URLClassLoader.close are commented out, the original jar can not be
  // modified or deleted.
  // If the calls are uncommented, while the program is waiting for input you can change the
  // output of Test.printMe and rebuild the jar. The program output will change accordingly
  // on subsequent iterations.
	public static void main(String... args) throws ClassNotFoundException,
			IOException, NoSuchMethodException, SecurityException,
			IllegalAccessException, IllegalArgumentException,
			InvocationTargetException {
		
		// FIXME: Replace with path to the jar containing Test.java
		String url = "jar:file:///C:/Users/Johannes/loci/test/target/scijava-tests-2.43.1-SNAPSHOT.jar!/";

		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
			URLClassLoader cl1 = new URLClassLoader(new URL[] { new URL(url) });
			Method m1 = cl1.loadClass("org.scijava.Test").getDeclaredMethod("printMe", null);

			// NB: with this commented, loaded jar can not be deleted.
//			cl1.close();

		while (!br.readLine().equals("end")) {
			URLClassLoader cl = new URLClassLoader(new URL[] { new URL(url) });
			Class<?> cls = cl.loadClass("org.scijava.Test");
			Method m = cls.getDeclaredMethod("printMe", null);
			System.out.print("M1 class: " + m1.getDeclaringClass() + " ");
			m1.invoke(null, null);
			System.out.print("M2 class: " + m.getDeclaringClass() + " ");
			m.invoke(null, null);
	
			// NB: with this commented, loaded jar can not be deleted.
//			cl.close();
		}
	}
}

Test.java

package org.scijava;

public class Test {


  public static void printMe() {

    System.out.println("This is message 1");

  }
}