Wish to prevent application starting threads

Question

Hi,
I wish to prevent my standalone java application from executing threads.
I ensure the permission,      java.lang.RuntimePermission "modifyThreadGroup" is not in the policy file.
According to http://java.sun.com/j2se/1.4.2/docs/guide/security/permissions.html, I believe the application should not be able to instantiate new thread objects.
To test it, I run the code:
          Runnable tonyRunnable = new Runnable() {
               public void run() {
                    System.out.println("tony says it's cool!");
          Thread t = new Thread(tonyRunnable);
          t.start();
          t.join();And it runs. I expect a security exception but don't get it. I am 100% confident my application has a security manager and policy file.
Any ideas?
Thanks.

Answer 1

You're not doing anything with ThreadGroups in the code above. The modifyThreadGroup target of RuntimePermission is for allowing:
"modification of thread groups, e.g., via calls to ThreadGroup destroy, getParent, resume, setDaemon, setMaxPriority, stop, and suspend methods"
There is no way to prevent an application from creating and starting its own threads.