sPath.getLoader(URLClassPath.java:203)
        at sun.misc.URLClassPath.getResource(URLClassPath.java:131)
        at java.net.URLClassLoader.findResource(URLClassLoader.java:342)
        at java.lang.ClassLoader.getResource(ClassLoader.java:680)
        at java.lang.ClassLoader.getResourceAsStream(ClassLoader.java:838)
        at java.beans.Beans$1.run(Beans.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.beans.Beans.instantiate(Beans.java:157)
        at java.beans.Beans.instantiate(Beans.java:55)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:21)

"Thread-0" prio=5 tid=0x820560 nid=0x1f6 waiting on monitor
[0xe83f000..0xe83fdf0]
        at sun.misc.URLClassPath.getLoader(URLClassPath.java:203)
        at sun.misc.URLClassPath.getResource(URLClassPath.java:131)
        at java.net.URLClassLoader.findResource(URLClassLoader.java:342)
        at java.lang.ClassLoader.getResource(ClassLoader.java:680)
        at java.lang.ClassLoader.getResourceAsStream(ClassLoader.java:838)
        at java.beans.Beans$1.run(Beans.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.beans.Beans.instantiate(Beans.java:157)
        at java.beans.Beans.instantiate(Beans.java:55)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:21)

"Signal Dispatcher" daemon prio=10 tid=0x815970 nid=0x16e waiting on monitor
[0..0]

"Finalizer" daemon prio=9 tid=0x814780 nid=0x174 waiting on monitor
[0xe53f000..0xe53fdf0]
        at java.lang.Object.wait(Native Method)
        at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:112)
        at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:127)
        at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:174)

"Reference Handler" daemon prio=10 tid=0x814330 nid=0x191 waiting on monitor
[0xe43f000..0
        at java.lang.Object.wait(Native Method)
        at java.lang.Object.wait(Object.java:424)
        at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:114)

"VM Thread" prio=5 tid=0x8138e0 nid=0x13c runnable

"VM Periodic Task Thread" prio=10 tid=0x815d40 nid=0x172 waiting on monitor



Conclusion
-----------

There is a very serious performance bottleneck in UrlClassPath. This
is a critical bug for us because we would like to be able to control
the security policies of the system.
(Review ID: 102536)
======================================================================


Name: skT45625 Date: 04/25/2000


java version "1.2.2"
HotSpot VM (1.0.1, mixed mode, build g)


This is a performance problem which we have seen in live installations
of our product(ATG Dynamo Application Server). We whittled this down
to a very simple example.

1. Create a simple program which instantiates beans from many threads

The main class
---------------

import java.io.*;
import java.beans.Beans;

/**
 * This class shows that the performance of sun.misc.UrlClassPath is
 * unacceptable.
 * <p>
 * Run the main method with a security policy specified where the security
 * policy grants all permissions. Then get a stack dump of the VM. You will
find
 * that the threads are most commonly found to be waiting on a monitor
 * in the sun.misc.UrlClassPath.getLoader(int) method.
 *
 */
public class UrlClassPathPerformance
 extends Thread
{
  public void run()
  {
    while (true) {
      try{
Object bean = Beans.instantiate(ClassLoader.getSystemClassLoader(),
"MyBean");
System.out.println("got bean: " + bean);
      }
      catch (IOException e) {
System.out.println("failure to get bean: " + e);
      }
      catch (ClassNotFoundException ce) {
System.out.println("class not found: " + ce);
      }
      
      try {
Thread.sleep((long)(10 * Math.random()));
      }
      catch (InterruptedException e) { }
    }
  }

  public static void main(String[] pArgs)
  {
    System.setSecurityManager(new SecurityManager());
    System.out.println("classloader = " + ClassLoader.getSystemClassLoader());
    for (int i=0; i < 20; i++)
      new UrlClassPathPerformance().start();
  }
}

The Bean class
--------------

public class MyBean
{
}



2. Run the program with a policy file which grants all permissions

The policy file
----------------
grant {
permission java.security.AllPermission;
};

The commands used
-----------------
set CLASSPATH=.;%CLASSPATH%

java -Djava.security.policy=java.policy UrlClassPathPerformance


3. Notice that this program is very slow - take a stack dump

The stack dump
--------------
"Thread-20" prio=5 tid=0x823100 nid=0x1a0 waiting on monitor [0..0x12fd90]

"Thread-19" prio=5 tid=0x822e10 nid=0x19a waiting on monitor
[0xfb3f000..0xfb3fdf0]
        at sun.misc.URLClassPath.getLoader(URLClassPath.java:203)
        at sun.misc.URLClassPath.getResource(URLClassPath.java:131)
        at java.net.URLClassLoader.findResource(URLClassLoader.java:342)
        at java.lang.ClassLoader.getResource(ClassLoader.java:680)
        at java.lang.ClassLoader.getResourceAsStream(ClassLoader.java:838)
        at java.beans.Beans$1.run(Beans.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.beans.Beans.instantiate(Beans.java:157)
        at java.beans.Beans.instantiate(Beans.java:55)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:21)

"Thread-18" prio=5 tid=0x822c50 nid=0x11e waiting on monitor
[0xfa3f000..0xfa3fdf0]
        at sun.misc.URLClassPath.getLoader(URLClassPath.java:203)
        at sun.misc.URLClassPath.getResource(URLClassPath.java:131)
        at java.net.URLClassLoader.findResource(URLClassLoader.java:342)
        at java.lang.ClassLoader.getResource(ClassLoader.java:680)
        at java.lang.ClassLoader.getResourceAsStream(ClassLoader.java:838)
        at java.beans.Beans$1.run(Beans.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.beans.Beans.instantiate(Beans.java:157)
        at java.beans.Beans.instantiate(Beans.java:55)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:21)

"Thread-17" prio=5 tid=0x822a90 nid=0x1fa waiting on monitor
[0xf93f000..0xf93fdf0]
        at sun.misc.URLClassPath.getLoader(URLClassPath.java:203)
        at sun.misc.URLClassPath.getResource(URLClassPath.java:131)
        at java.net.URLClassLoader.findResource(URLClassLoader.java:342)
        at java.lang.ClassLoader.getResource(ClassLoader.java:680)
        at java.lang.ClassLoader.getResourceAsStream(ClassLoader.java:838)
        at java.beans.Beans$1.run(Beans.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.beans.Beans.instantiate(Beans.java:157)
        at java.beans.Beans.instantiate(Beans.java:55)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:21)

"Thread-16" prio=5 tid=0x8228d0 nid=0x217 waiting on monitor
[0xf83f000..0xf83fdf0]
        at java.lang.Thread.sleep(Native Method)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:33)

"Thread-15" prio=5 tid=0x822710 nid=0x196 waiting on monitor
[0xf73f000..0xf73fdf0]
        at sun.misc.URLClassPath.getLoader(URLClassPath.java:203)
        at sun.misc.URLClassPath.getResource(URLClassPath.java:131)
        at java.net.URLClassLoader.findResource(URLClassLoader.java:342)
        at java.lang.ClassLoader.getResource(ClassLoader.java:680)
        at java.lang.ClassLoader.getResourceAsStream(ClassLoader.java:838)
        at java.beans.Beans$1.run(Beans.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.beans.Beans.instantiate(Beans.java:157)
        at java.beans.Beans.instantiate(Beans.java:55)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:21)

"Thread-14" prio=5 tid=0x822550 nid=0x1cc waiting on monitor
[0xf63f000..0xf63fdf0]
        at sun.misc.URLClassPath.getLoader(URLClassPath.java:203)
        at sun.misc.URLClassPath.getResource(URLClassPath.java:131)
        at java.net.URLClassLoader.findResource(URLClassLoader.java:342)
        at java.lang.ClassLoader.getResource(ClassLoader.java:680)
        at java.lang.ClassLoader.getResourceAsStream(ClassLoader.java:838)
        at java.beans.Beans$1.run(Beans.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.beans.Beans.instantiate(Beans.java:157)
        at java.beans.Beans.instantiate(Beans.java:55)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:21)

"Thread-13" prio=5 tid=0x822390 nid=0x78 waiting on monitor
[0xf53f000..0xf53fdf0]
        at sun.misc.URLClassPath.getLoader(URLClassPath.java:203)
        at sun.misc.URLClassPath.getResource(URLClassPath.java:131)
        at java.net.URLClassLoader.findResource(URLClassLoader.java:342)
        at java.lang.ClassLoader.getResource(ClassLoader.java:680)
        at java.lang.ClassLoader.getResourceAsStream(ClassLoader.java:838)
        at java.beans.Beans$1.run(Beans.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.beans.Beans.instantiate(Beans.java:157)
        at java.beans.Beans.instantiate(Beans.java:55)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:21)

"Thread-12" prio=5 tid=0x8221d0 nid=0x128 waiting on monitor
[0xf43f000..0xf43fdf0]
        at sun.misc.URLClassPath.getLoader(URLClassPath.java:203)
        at sun.misc.URLClassPath.getResource(URLClassPath.java:131)
        at java.net.URLClassLoader.findResource(URLClassLoader.java:342)
        at java.lang.ClassLoader.getResource(ClassLoader.java:680)
        at java.lang.ClassLoader.getResourceAsStream(ClassLoader.java:838)
        at java.beans.Beans$1.run(Beans.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.beans.Beans.instantiate(Beans.java:157)
        at java.beans.Beans.instantiate(Beans.java:55)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:21)

"Thread-11" prio=5 tid=0x821f00 nid=0x185 waiting on monitor
[0xf33f000..0xf33fdf0]
        at sun.misc.URLClassPath.getLoader(URLClassPath.java:203)
        at sun.misc.URLClassPath.getResource(URLClassPath.java:131)
        at java.net.URLClassLoader.findResource(URLClassLoader.java:342)
        at java.lang.ClassLoader.getResource(ClassLoader.java:680)
        at java.lang.ClassLoader.getResourceAsStream(ClassLoader.java:838)
        at java.beans.Beans$1.run(Beans.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.beans.Beans.instantiate(Beans.java:157)
        at java.beans.Beans.instantiate(Beans.java:55)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:21)

"Thread-10" prio=5 tid=0x821d40 nid=0x127 waiting on monitor
[0xf23f000..0xf23fdf0]
        at sun.misc.URLClassPath.getLoader(URLClassPath.java:203)
        at sun.misc.URLClassPath.getResource(URLClassPath.java:131)
        at java.net.URLClassLoader.findResource(URLClassLoader.java:342)
        at java.lang.ClassLoader.getResource(ClassLoader.java:680)
        at java.lang.ClassLoader.getResourceAsStream(ClassLoader.java:838)
        at java.beans.Beans$1.run(Beans.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.beans.Beans.instantiate(Beans.java:157)
        at java.beans.Beans.instantiate(Beans.java:55)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:21)

"Thread-9" prio=5 tid=0x821b80 nid=0x17c runnable [0xf13f000..0xf13fdf0]
        at sun.misc.URLClassPath.getLoader(URLClassPath.java:203)
        at sun.misc.URLClassPath.getResource(URLClassPath.java:131)
        at java.net.URLClassLoader.findResource(URLClassLoader.java:342)
        at java.lang.ClassLoader.getResource(ClassLoader.java:680)
        at java.lang.ClassLoader.getResourceAsStream(ClassLoader.java:838)
        at java.beans.Beans$1.run(Beans.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.beans.Beans.instantiate(Beans.java:157)
        at java.beans.Beans.instantiate(Beans.java:55)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:21)

"Thread-8" prio=5 tid=0x8219c0 nid=0x198 waiting on monitor
[0xf03f000..0xf03fdf0]
        at sun.misc.URLClassPath.getLoader(URLClassPath.java:203)
        at sun.misc.URLClassPath.getResource(URLClassPath.java:131)
        at java.net.URLClassLoader.findResource(URLClassLoader.java:342)
        at java.lang.ClassLoader.getResource(ClassLoader.java:680)
        at java.lang.ClassLoader.getResourceAsStream(ClassLoader.java:838)
        at java.beans.Beans$1.run(Beans.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.beans.Beans.instantiate(Beans.java:157)
        at java.beans.Beans.instantiate(Beans.java:55)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:21)

"Thread-7" prio=5 tid=0x821800 nid=0x11c runnable [0xef3f000..0xef3fdf0]
        at sun.misc.URLClassPath.getLoader(URLClassPath.java:203)
        at sun.misc.URLClassPath.getResource(URLClassPath.java:131)
        at java.net.URLClassLoader.findResource(URLClassLoader.java:342)
        at java.lang.ClassLoader.getResource(ClassLoader.java:680)
        at java.lang.ClassLoader.getResource(ClassLoader.java:675)
        at java.lang.ClassLoader.getResourceAsStream(ClassLoader.java:838)
        at java.beans.Beans$1.run(Beans.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.beans.Beans.instantiate(Beans.java:157)
        at java.beans.Beans.instantiate(Beans.java:55)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:21)

"Thread-6" prio=5 tid=0x821640 nid=0x21c waiting on monitor
[0xee3f000..0xee3fdf0]
        at sun.misc.URLClassPath.getLoader(URLClassPath.java:203)
        at sun.misc.URLClassPath.getResource(URLClassPath.java:131)
        at java.net.URLClassLoader.findResource(URLClassLoader.java:342)
        at java.lang.ClassLoader.getResource(ClassLoader.java:680)
        at java.lang.ClassLoader.getResourceAsStream(ClassLoader.java:838)
        at java.beans.Beans$1.run(Beans.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.beans.Beans.instantiate(Beans.java:157)
        at java.beans.Beans.instantiate(Beans.java:55)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:21)

"Thread-5" prio=5 tid=0x821480 nid=0x13d runnable [0xed3f000..0xed3fdf0]
        at sun.misc.URLClassPath.getLoader(URLClassPath.java:203)
        at sun.misc.URLClassPath.getResource(URLClassPath.java:131)
        at java.net.URLClassLoader.findResource(URLClassLoader.java:342)
        at java.lang.ClassLoader.getResource(ClassLoader.java:680)
        at java.lang.ClassLoader.getResourceAsStream(ClassLoader.java:838)
        at java.beans.Beans$1.run(Beans.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.beans.Beans.instantiate(Beans.java:157)
        at java.beans.Beans.instantiate(Beans.java:55)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:21)

"Thread-4" prio=5 tid=0x8212c0 nid=0x43 waiting on monitor
[0xec3f000..0xec3fdf0]
        at sun.misc.URLClassPath.getLoader(URLClassPath.java:203)
        at sun.misc.URLClassPath.getResource(URLClassPath.java:131)
        at java.net.URLClassLoader.findResource(URLClassLoader.java:342)
        at java.lang.ClassLoader.getResource(ClassLoader.java:680)
        at java.lang.ClassLoader.getResourceAsStream(ClassLoader.java:838)
        at java.beans.Beans$1.run(Beans.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.beans.Beans.instantiate(Beans.java:157)
        at java.beans.Beans.instantiate(Beans.java:55)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:21)

"Thread-3" prio=5 tid=0x821100 nid=0x141 waiting on monitor
[0xeb3f000..0xeb3fdf0]
        at sun.misc.URLClassPath.getLoader(URLClassPath.java:203)
        at sun.misc.URLClassPath.getResource(URLClassPath.java:131)
        at java.net.URLClassLoader.findResource(URLClassLoader.java:342)
        at java.lang.ClassLoader.getResource(ClassLoader.java:680)
        at java.lang.ClassLoader.getResourceAsStream(ClassLoader.java:838)
        at java.beans.Beans$1.run(Beans.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.beans.Beans.instantiate(Beans.java:157)
        at java.beans.Beans.instantiate(Beans.java:55)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:21)

"Thread-2" prio=5 tid=0x820920 nid=0x1dc waiting on monitor
[0xea3f000..0xea3fdf0]
        at sun.misc.URLClassPath.getLoader(URLClassPath.java:203)
        at sun.misc.URLClassPath.getResource(URLClassPath.java:131)
        at java.net.URLClassLoader.findResource(URLClassLoader.java:342)
        at java.lang.ClassLoader.getResource(ClassLoader.java:680)
        at java.lang.ClassLoader.getResourceAsStream(ClassLoader.java:838)
        at java.beans.Beans$1.run(Beans.java:162)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.beans.Beans.instantiate(Beans.java:157)
        at java.beans.Beans.instantiate(Beans.java:55)
        at UrlClassPathPerformance.run(UrlClassPathPerformance.java:21)

"Thread-1" prio=5 tid=0x820760 nid=0x1c8 waiting on monitor
[0xe93f000..0xe93fdf0]
        at sun.misc.URLClas