Fix Bug 840: DefaultEDTUtil.restart() shall only reuse ThreadGroup (tg) is not destroyed, otherwise use current thread's tg.

With jdk7u40, when re-launching a NEWT applet (JOGLNewtApplet1Run),
i.e. via browser back and forth, the following exception happens:

java.lang.RuntimeException: java.lang.IllegalThreadStateException
    at com.jogamp.newt.awt.applet.JOGLNewtApplet1Run.init(JOGLNewtApplet1Run.java:218)
    at com.sun.deploy.uitoolkit.impl.awt.AWTAppletAdapter.init(Unknown Source)
    at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.IllegalThreadStateException
    at java.lang.ThreadGroup.addUnstarted(Unknown Source)
    at java.lang.Thread.init(Unknown Source)
    at java.lang.Thread.<init>(Unknown Source)
    at jogamp.newt.DefaultEDTUtil$NEDT.<init>(DefaultEDTUtil.java:280)
    at jogamp.newt.DefaultEDTUtil.restart(DefaultEDTUtil.java:91)
    at jogamp.newt.DisplayImpl.runOnEDTIfAvail(DisplayImpl.java:231)
    at jogamp.newt.WindowImpl.runOnEDTIfAvail(WindowImpl.java:1758)
    at jogamp.newt.WindowImpl.setUndecorated(WindowImpl.java:1477)
    at com.jogamp.newt.opengl.GLWindow.setUndecorated(GLWindow.java:278)
    at com.jogamp.newt.awt.applet.JOGLNewtApplet1Run.init(JOGLNewtApplet1Run.java:188)
    ... 3 more

This is due to 7u40's changed ThreadGroup (tg) lifecycle, i.e. the tg is destroyed.
In such case, DefaultEDTUtil.restart() shall use the current threads tg.

1 files changed, 6 insertions, 1 deletions

diff --git a/src/newt/classes/jogamp/newt/DefaultEDTUtil.java b/src/newt/classes/jogamp/newt/DefaultEDTUtil.java
index a229a0512..5794d4ae9 100644
--- a/src/newt/classes/jogamp/newt/DefaultEDTUtil.java
+++ b/src/newt/classes/jogamp/newt/DefaultEDTUtil.java
@@ -38,6 +38,7 @@
 package jogamp.newt;
 
 import java.util.ArrayList;
+
 import javax.media.nativewindow.NativeWindowException;
 
 import jogamp.common.util.locks.LockDebugUtil;
@@ -50,7 +51,7 @@ public class DefaultEDTUtil implements EDTUtil {
     public static final boolean DEBUG = Debug.debug("EDT");
 
     private final Object edtLock = new Object(); // locking the EDT start/stop state
-    private final ThreadGroup threadGroup; 
+    private /* final */ ThreadGroup threadGroup; 
     private final String name;
     private final Runnable dispatchMessages;
     private NEDT edt = null;
@@ -88,6 +89,10 @@ public class DefaultEDTUtil implements EDTUtil {
                 System.err.println(Thread.currentThread()+": Default-EDT reset - edt: "+edt);
             }
             if( edt.getState() != Thread.State.NEW ) {
+                if( null != threadGroup && threadGroup.isDestroyed() ) {
+                    // best thing we can do is to use this thread's TG
+                    threadGroup = Thread.currentThread().getThreadGroup();
+                }
                 edt = new NEDT(threadGroup, name);
                 edt.setDaemon(true); // don't stop JVM from shutdown ..
             }