--- a/jdk/src/java.desktop/unix/classes/sun/awt/X11/XWindowPeer.java	Tue Jun 23 11:59:27 2015 +0300
+++ b/jdk/src/java.desktop/unix/classes/sun/awt/X11/XWindowPeer.java	Mon Jun 22 15:43:40 2015 +0300
@@ -682,28 +682,33 @@
         GraphicsConfiguration newGC = null;
         Rectangle screenBounds;
 
-        for (int i = 0; i < gds.length; i++) {
-            screenBounds = gds[i].getDefaultConfiguration().getBounds();
-            if (newBounds.intersects(screenBounds)) {
-                horizAmt = Math.min(newBounds.x + newBounds.width,
-                                    screenBounds.x + screenBounds.width) -
-                           Math.max(newBounds.x, screenBounds.x);
-                vertAmt = Math.min(newBounds.y + newBounds.height,
-                                   screenBounds.y + screenBounds.height)-
-                          Math.max(newBounds.y, screenBounds.y);
-                intAmt = horizAmt * vertAmt;
-                if (intAmt == area) {
-                    // Completely on this screen - done!
-                    newScreenNum = i;
-                    newGC = gds[i].getDefaultConfiguration();
-                    break;
-                }
-                if (intAmt > largestAmt) {
-                    largestAmt = intAmt;
-                    newScreenNum = i;
-                    newGC = gds[i].getDefaultConfiguration();
+        XToolkit.awtUnlock();
+        try {
+            for (int i = 0; i < gds.length; i++) {
+                screenBounds = gds[i].getDefaultConfiguration().getBounds();
+                if (newBounds.intersects(screenBounds)) {
+                    horizAmt = Math.min(newBounds.x + newBounds.width,
+                                        screenBounds.x + screenBounds.width) -
+                               Math.max(newBounds.x, screenBounds.x);
+                    vertAmt = Math.min(newBounds.y + newBounds.height,
+                                       screenBounds.y + screenBounds.height)-
+                              Math.max(newBounds.y, screenBounds.y);
+                    intAmt = horizAmt * vertAmt;
+                    if (intAmt == area) {
+                        // Completely on this screen - done!
+                        newScreenNum = i;
+                        newGC = gds[i].getDefaultConfiguration();
+                        break;
+                    }
+                    if (intAmt > largestAmt) {
+                        largestAmt = intAmt;
+                        newScreenNum = i;
+                        newGC = gds[i].getDefaultConfiguration();
+                    }
                 }
             }
+        } finally {
+            XToolkit.awtLock();
         }
         if (newScreenNum != curScreenNum) {
             if (log.isLoggable(PlatformLogger.Level.FINEST)) {

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/awt/FullScreen/MultimonFullscreenTest/MultimonDeadlockTest.java	Mon Jun 22 15:43:40 2015 +0300
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+  @test
+  @bug 8129116
+  @summary Deadlock with multimonitor fullscreen windows.
+  @run main/timeout=20 MultimonDeadlockTest
+ */
+import java.awt.*;
+import java.awt.event.WindowAdapter;
+import java.awt.event.WindowEvent;
+import java.lang.reflect.InvocationTargetException;
+
+public class MultimonDeadlockTest {
+
+    public static void main(String argv[]) {
+        final GraphicsDevice[] devices = GraphicsEnvironment
+                .getLocalGraphicsEnvironment()
+                .getScreenDevices();
+        if (devices.length < 2) {
+            System.out.println("It's a multiscreen test... skipping!");
+            return;
+        }
+
+        Frame frames[] = new Frame[devices.length];
+        try {
+            EventQueue.invokeAndWait(() -> {
+                for (int i = 0; i < devices.length; i++) {
+                    frames[i] = new Frame();
+                    frames[i].setSize(100, 100);
+                    frames[i].setBackground(Color.BLUE);
+                    devices[i].setFullScreenWindow(frames[i]);
+                }
+            });
+            Thread.sleep(5000);
+        } catch (InterruptedException | InvocationTargetException ex) {
+        } finally {
+            for (int i = 0; i < devices.length; i++) {
+                devices[i].setFullScreenWindow(null);
+                frames[i].dispose();
+            }
+        }
+
+    }
+}