import java.net.URL;
import java.io.File;
import java.net.URLClassLoader;
import sun.net.www.ParseUtil;

/*
 * javac G1Checker2.java && mkdir -p foo && mv FooFoo.class foo/
 *
 * java -cp . G1Checker2
 * java -cp . G1Checker2 classloader
 *
 * java -cp . -XX:+PrintGCDetails -XX:+UseG1GC G1Checker2
 * java -cp . -XX:+PrintGCDetails -XX:+UseG1GC G1Checker2 classloader
 */
public class G1Checker2 {
  static URLClassLoader u1, u2, u3;
  static Class<?> c1, c2, c3;

  public static void main(String[] args) throws Exception {
    boolean classLoader = false;
    if (args.length > 0) {
      classLoader = "classloader".equals(args[0]);
    }
    String klassPath = "FooFoo";
    ClassLoader loader = G1Checker.class.getClassLoader();

    //loading a class referenced in the parent url loader
    Class<?> theKlass;
    while (true) {
      File file = new File("foo");
      file = file.getCanonicalFile();
      URL urls[] = new URL[1];
      urls[0] = ParseUtil.fileToEncodedURL(file);
      URLClassLoader urlClassLoader = new URLClassLoader(urls, loader);
      u3 = u2;
      u2 = u1;
      u1 = urlClassLoader;
            
      if (classLoader) {
        theKlass = urlClassLoader.loadClass(klassPath);
      } else {
        //loading it this way creates lots of references in the dictionary
        theKlass = Class.forName(klassPath, false, urlClassLoader);
      }
      theKlass.toString();
      c3 = c2;
      c2 = c1;
      c1 = theKlass;
      //System.out.println("Loader = " + theKlass.getClassLoader());
    }
  }
}

class FooFoo {

}