8078606: Deadlock in awt clipboard

Reviewed-by: azvegint, bae

src/solaris/classes/sun/awt/X11/XClipboard.java

@@ -156,7 +156,14 @@ public final class XClipboard extends SunClipboard implements OwnershipListener
         isSelectionNotifyProcessed = true;
 
         boolean mustSchedule = false;
+        XToolkit.awtLock();
+        try {
             synchronized (XClipboard.classLock) {
+                try {
+                    Thread.sleep(70);
+                } catch (InterruptedException e) {
+                    e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
+                }
                 if (targetsAtom2Clipboard == null) {
                     targetsAtom2Clipboard = new HashMap<Long, XClipboard>(2);
                 }
@@ -170,6 +177,9 @@ public final class XClipboard extends SunClipboard implements OwnershipListener
             if (mustSchedule) {
                 XToolkit.schedule(new CheckChangeTimerTask(), XClipboard.getPollInterval());
             }
+        } finally {
+            XToolkit.awtUnlock();
+        }
     }
 
     private static class CheckChangeTimerTask implements Runnable {

src/solaris/classes/sun/awt/X11/XRootWindow.java

@@ -31,20 +31,24 @@ package sun.awt.X11;
  * common logical ancestor
  */
 class XRootWindow extends XBaseWindow {
-    private static XRootWindow xawtRootWindow = null;
-    static XRootWindow getInstance() {
+    private static class LazyHolder {
+        private static final XRootWindow xawtRootWindow;
+
+        static {
             XToolkit.awtLock();
             try {
-            if (xawtRootWindow == null) {
                 xawtRootWindow = new XRootWindow();
                 xawtRootWindow.init(xawtRootWindow.getDelayedParams().delete(DELAYED));
-            }
-            return xawtRootWindow;
             } finally {
                 XToolkit.awtUnlock();
             }
         }
 
+    }
+    static XRootWindow getInstance() {
+        return LazyHolder.xawtRootWindow;
+    }
+
     private XRootWindow() {
         super(new XCreateWindowParams(new Object[] { DELAYED, Boolean.TRUE,
                                                      EVENT_MASK, XConstants.StructureNotifyMask }));