There is some exception threw in Java Console during JDK7-b45 SWAT testing.

Bundles location: http://jre.sfbay/java/re/jdk/7/nightly/bundles/<PLATFORM-ARCH>/latest
OS tested: Windows Vista, Solaris Sparc 10, RHEL5.2

How to reproduce:
1. Install jre from the location above.
2. Use the browser to load SwingSet2 Applet or Java 2D from http://java.sun.com/products/plugin/1.5.0/demos/applets.html
3. The exception is printed to the Java Console when the applet is closed.
This is the stack trace of the exception:
Exception in thread "TimerQueue" java.lang.IllegalMonitorStateException
at java.util.concurrent.locks.ReentrantLock$Sync.tryRelease(Unknown Source)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.release(Unknown Source)
at java.util.concurrent.locks.ReentrantLock.unlock(Unknown Source)
at java.util.concurrent.DelayQueue.take(Unknown Source)
at javax.swing.TimerQueue.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Exception in thread "SwingWorker-pool-1-thread-1" java.security.AccessControlException: access denied (java.lang.RuntimePermission modifyThreadGroup)
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at sun.applet.AppletSecurity.checkAccess(Unknown Source)
at java.lang.ThreadGroup.checkAccess(Unknown Source)
at java.lang.Thread.init(Unknown Source)
at java.lang.Thread.<init>(Unknown Source)
at java.util.concurrent.Executors$DefaultThreadFactory.newThread(Unknown Source)
at javax.swing.SwingWorker$6.newThread(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.<init>(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.addWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.processWorkerExit(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

It's a regression starting from b15.