3 files changed, 25 insertions, 19 deletions

diff --git a/src/jogl/classes/jogamp/opengl/GLContextImpl.java b/src/jogl/classes/jogamp/opengl/GLContextImpl.java
index ea024e691..4ef8b9750 100644
--- a/src/jogl/classes/jogamp/opengl/GLContextImpl.java
+++ b/src/jogl/classes/jogamp/opengl/GLContextImpl.java
@@ -233,12 +233,10 @@ public abstract class GLContextImpl extends GLContext {
     if ( !lock.isOwner(Thread.currentThread()) ) {
         throw new GLException("Context not current on current thread "+Thread.currentThread().getName()+": "+this);
     }
-    final boolean actualRelease = force || lock.getHoldCount() == 1 ;
+    final boolean actualRelease = ( force || lock.getHoldCount() == 1 ) && 0 != contextHandle;
     try {
         if( actualRelease ) {
-            if (contextHandle != 0) { // allow dbl-release
-                releaseImpl();
-            }
+            releaseImpl();
         }
     } finally {
       // exception prone ..
@@ -269,11 +267,16 @@ public abstract class GLContextImpl extends GLContext {
           try {
               // Must hold the lock around the destroy operation to make sure we
               // don't destroy the context while another thread renders to it.
-              // FIXME: This is actually impossible now, since we acquired the surface lock already,
-              //        which is a prerequisite to acquire the context lock.
-              lock.lock(); // holdCount++ -> 1 or 2
+              lock.lock(); // holdCount++ -> 1 - 3 (1: not locked, 2-3: destroy while rendering)
               if ( lock.getHoldCount() > 2 ) {
-                  throw new GLException(getThreadName() + ": Lock was hold more than once - makeCurrent/release imbalance: "+lock);
+                  final String msg = getThreadName() + ": GLContextImpl.destroy: obj " + toHexString(hashCode()) + ", ctx " + toHexString(contextHandle);
+                  if (DEBUG || TRACE_SWITCH) {
+                      System.err.println(msg+" - Lock was hold more than once - makeCurrent/release imbalance: "+lock);
+                      Thread.dumpStack();
+                  }
+                  if ( lock.getHoldCount() > 3 ) {
+                      throw new GLException(msg+" - Lock was hold more than twice - makeCurrent/release imbalance: "+lock);
+                  }
               }
               try {
                   // release current context
diff --git a/src/jogl/classes/jogamp/opengl/GLDrawableImpl.java b/src/jogl/classes/jogamp/opengl/GLDrawableImpl.java
index c843e5571..b3884830a 100644
--- a/src/jogl/classes/jogamp/opengl/GLDrawableImpl.java
+++ b/src/jogl/classes/jogamp/opengl/GLDrawableImpl.java
@@ -66,7 +66,7 @@ public abstract class GLDrawableImpl implements GLDrawable {
    */
   public abstract GLDynamicLookupHelper getGLDynamicLookupHelper();
 
-  public GLDrawableFactoryImpl getFactoryImpl() {
+  public final GLDrawableFactoryImpl getFactoryImpl() {
     return (GLDrawableFactoryImpl) getFactory();
   }
 
@@ -86,6 +86,9 @@ public abstract class GLDrawableImpl implements GLDrawable {
 
   @Override
   public final void swapBuffers() throws GLException {
+    if( !realized ) {
+        return; // destroyed already
+    }
     GLCapabilitiesImmutable caps = (GLCapabilitiesImmutable)surface.getGraphicsConfiguration().getChosenCapabilities();
     if ( caps.getDoubleBuffered() ) {
         if(!surface.surfaceSwap()) {
@@ -112,12 +115,12 @@ public abstract class GLDrawableImpl implements GLDrawable {
   }
   protected abstract void swapBuffersImpl();
 
-  public static String toHexString(long hex) {
+  public final static String toHexString(long hex) {
     return "0x" + Long.toHexString(hex);
   }
 
   @Override
-  public GLProfile getGLProfile() {
+  public final GLProfile getGLProfile() {
     return requestedCapabilities.getGLProfile();
   }
 
@@ -126,7 +129,7 @@ public abstract class GLDrawableImpl implements GLDrawable {
     return  (GLCapabilitiesImmutable) surface.getGraphicsConfiguration().getChosenCapabilities();
   }
 
-  public GLCapabilitiesImmutable getRequestedGLCapabilities() {
+  public final GLCapabilitiesImmutable getRequestedGLCapabilities() {
     return requestedCapabilities;
   }
 
@@ -147,7 +150,7 @@ public abstract class GLDrawableImpl implements GLDrawable {
   }
 
   @Override
-  public GLDrawableFactory getFactory() {
+  public final GLDrawableFactory getFactory() {
     return factory;
   }
 
@@ -187,7 +190,7 @@ public abstract class GLDrawableImpl implements GLDrawable {
   protected abstract void setRealizedImpl();
 
   @Override
-  public synchronized boolean isRealized() {
+  public final synchronized boolean isRealized() {
     return realized;
   }
 
@@ -201,11 +204,11 @@ public abstract class GLDrawableImpl implements GLDrawable {
     return surface.getHeight();
   }
 
-  public int lockSurface() throws GLException {
+  public final int lockSurface() throws GLException {
     return surface.lockSurface();
   }
 
-  public void unlockSurface() {
+  public final void unlockSurface() {
     surface.unlockSurface();
   }
 
diff --git a/src/jogl/classes/jogamp/opengl/GLPbufferImpl.java b/src/jogl/classes/jogamp/opengl/GLPbufferImpl.java
index 9b3def434..0ed3be48b 100644
--- a/src/jogl/classes/jogamp/opengl/GLPbufferImpl.java
+++ b/src/jogl/classes/jogamp/opengl/GLPbufferImpl.java
@@ -88,16 +88,16 @@ public class GLPbufferImpl implements GLPbuffer {
   }
 
   @Override
-  public GLContext createContext(GLContext shareWith) {
+  public final GLContext createContext(GLContext shareWith) {
     return pbufferDrawable.createContext(shareWith);
   }
 
   @Override
-  public void setRealized(boolean realized) {
+  public final void setRealized(boolean realized) {
   }
 
   @Override
-  public boolean isRealized() {
+  public final boolean isRealized() {
     return true;
   }