Easy to produce - Memory Leak in JVM Using thread

Question

I was just debugging the problem with our server and got this error (not from the original code, I reproduced it with small code)
at java.lang.Thread.run(Unknown Source)
java.lang.OutOfMemoryError: unable to create new native thread
at java.lang.Thread.start0(Native Method)
at java.lang.Thread.start(Unknown Source)
at SomeObject.resursiveThreadGeneratorMethod(ThreadRecursionLeak.java:12
at ClientThread.run(ThreadRecursionLeak.java:27)
it is just a simple program generating thread recursively with a lock on an object
import java.lang.Runnable;
import java.lang.Thread;
//     <<Objec/Monitor Class>>
     class SomeObject{
          public synchronized void resursiveThreadGeneratorMethod(int threadNumber, int k){
               if(k<=0)
                    return;
               else{
                    System.out.println("Thread: "+threadNumber + "call number: "+k);
                    Thread thread=new Thread(new ClientThread(this));
                    thread.start();
                    resursiveThreadGeneratorMethod(threadNumber,k-1);
//     <<Thread Class>>
     class ClientThread implements Runnable{
          SomeObject someObject=null;
          public static int threadNumber;
          public ClientThread(SomeObject someObject){
               this.someObject=someObject;
               threadNumber++;
          public void run(){
               someObject.resursiveThreadGeneratorMethod(this.threadNumber,10);
//     <<Driver Class>>
     public class ThreadRecursionLeak{
          public static void main(String [] args){
               SomeObject someObject=new SomeObject();
               Thread thread=new Thread(new ClientThread(someObject));
               thread.start();
is there any way I can monitor JVM memory status (programatically), kill those threads leading to memory leak and send notification to the system admin.
We run JVM 1.4 on the server and need to address this issue as we do not have control over the code that can be submitted to the server, we just do some checks and then let it run on the servers.
Our main requirement is to keep JVM alive and kill all those code and report them.
Message was edited by:
rajanikant_malviya

Answer 1

You can monitor the JVM with the
[url=http://java.sun.com/j2se/1.4.2/docs/guide/jvmpi/i
ndex.html]JVMPI if you're using the Sun JVM.This is native code that basically gets
notified anytime the JVM does something
interesting.
However, you're going to have a very difficult time
catching code that does what the code you show does.
I'm not sure I understand your environment - you
allow people to submit code and you run it? Are you
running it in the same JVM as your server? That
seems like a huge issue. A simple System.exit()
code will take down your server.
Let us know some more details.
We are actually having a portal through witch users can submit their code, witch are basically utility codes for different operations teams.
we then provide a way to schedule them.
At the background, we are having 6 (Win) servers where at each server we are having 20 to 25 users on different ports (managed by our application) running there own JVMs. When a schedule is met we just invoke a servlet (on any free port) and pass code id (stored in DB). And this servlet is responsible for compilation and exicution of the code (We just use Runtime to fork this new process).
I don't know, but is there any way through witch I can monitor this process and restrict to generate threads recursively???