FULL PRODUCT VERSION :
java version "1.8.0-ea"
Java(TM) SE Runtime Environment (build 1.8.0-ea-b49)
Java HotSpot(TM) 64-Bit Server VM (build 24.0-b16, mixed mode)

AND

java version "1.7.0_06-ea"
Java(TM) SE Runtime Environment (build 1.7.0_06-ea-b09)
Java HotSpot(TM) Server VM (build 23.0-b21, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Fedora Linux 17

A DESCRIPTION OF THE PROBLEM :
When running FileDialogDropTargetTest regression test, I get occasionally deadlocks, with the following stack trace:

Name: XToolkt-Shutdown-Thread
State: WAITING on java.util.concurrent.locks.ReentrantLock$NonfairSync@4c92e44a owned by: AWT-XAWT
  Total blocked: 0 Total waited: 1
Stack trace:
sun.misc.Unsafe.park(Native Method)
java.util.concurrent.locks.LockSupport.park(LockSupport.java:186)
java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:834)
java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:867)
java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1197)
java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLock.java:214)
java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:290)
sun.awt.SunToolkit.awtLock(SunToolkit.java:245)
sun.awt.X11.XAtom.<init>(XAtom.java:265)
sun.awt.X11.XAtom.<init>(XAtom.java:232)
sun.awt.X11.XAtom.get(XAtom.java:178)
sun.awt.X11.XSystemTrayPeer.<clinit>(XSystemTrayPeer.java:52)
sun.awt.X11.XToolkit$1$1.run(XToolkit.java:326)

Name: AWT-XAWT
State: BLOCKED on java.awt.Component$AWTTreeLock@523a37ea owned by: main
  Total blocked: 2 Total waited: 76
Stack trace:
sun.awt.X11.XWindow.getLocationOnScreen(XWindow.java:1390)
sun.awt.X11.XTextAreaPeer.pSetCursor(XTextAreaPeer.java:188)
sun.awt.X11.XComponentPeer.pSetCursor(XComponentPeer.java:733)
sun.awt.X11.XWindow.handleXCrossingEvent(XWindow.java:956)
sun.awt.X11.XBaseWindow.dispatchEvent(XBaseWindow.java:1106)
sun.awt.X11.XBaseWindow.dispatchToWindow(XBaseWindow.java:1066)
sun.awt.X11.XToolkit.dispatchEvent(XToolkit.java:565)
sun.awt.X11.XToolkit.run(XToolkit.java:674)
sun.awt.X11.XToolkit.run(XToolkit.java:595)
java.lang.Thread.run(Thread.java:722)

Name: main
State: WAITING on java.util.concurrent.locks.ReentrantLock$NonfairSync@4c92e44a owned by: AWT-XAWT
  Total blocked: 11 Total waited: 280
Stack trace:
sun.misc.Unsafe.park(Native Method)
java.util.concurrent.locks.LockSupport.park(LockSupport.java:186)
java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:834)
java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:867)
java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1197)
java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLock.java:214)
java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:290)
sun.awt.SunToolkit.awtLock(SunToolkit.java:245)
sun.awt.X11.GtkFileDialogPeer.setVisible(GtkFileDialogPeer.java:109)
java.awt.Dialog.conditionalShow(Dialog.java:936)
   - locked java.awt.Component$AWTTreeLock@523a37ea
java.awt.Dialog.show(Dialog.java:1038)
FileDialogDropTargetTest.main(FileDialogDropTargetTest.java:65)




DEADLOCK with jdk7:

Name: Thread-93
State: BLOCKED on java.awt.Component$AWTTreeLock@268109 owned by: main
  Total blocked: 1 Total waited: 0
Stack trace:
java.awt.Dialog.hideAndDisposePreHandler(Dialog.java:1138)
java.awt.Dialog.hide(Dialog.java:1168)
java.awt.Component.show(Component.java:1653)
java.awt.Component.setVisible(Component.java:1603)
java.awt.Window.setVisible(Window.java:1014)
java.awt.Dialog.setVisible(Dialog.java:1003)
sun.awt.X11.GtkFileDialogPeer$1.run(GtkFileDialogPeer.java:115)

Name: main
State: WAITING on java.util.concurrent.locks.ReentrantLock$NonfairSync@ebe07e owned by: AWT-XAWT
  Total blocked: 119 Total waited: 1,217
Stack trace:
sun.misc.Unsafe.park(Native Method)
java.util.concurrent.locks.LockSupport.park(LockSupport.java:186)
java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:834)
java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:867)
java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1197)
java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLock.java:214)
java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:290)
sun.awt.SunToolkit.awtLock(SunToolkit.java:245)
sun.awt.X11.GtkFileDialogPeer.setVisible(GtkFileDialogPeer.java:109)
java.awt.Dialog.conditionalShow(Dialog.java:936)
   - locked java.awt.Component$AWTTreeLock@268109
java.awt.Dialog.show(Dialog.java:1038)
FileDialogDropTargetTest.main(FileDialogDropTargetTest.java:65)

Name: AWT-XAWT
State: BLOCKED on java.awt.Component$AWTTreeLock@268109 owned by: main
  Total blocked: 2 Total waited: 441
Stack trace:
sun.awt.X11.XWindow.getLocationOnScreen(XWindow.java:1390)
sun.awt.X11.XTextAreaPeer.pSetCursor(XTextAreaPeer.java:188)
sun.awt.X11.XComponentPeer.pSetCursor(XComponentPeer.java:733)
sun.awt.X11.XWindow.handleXCrossingEvent(XWindow.java:956)
sun.awt.X11.XBaseWindow.dispatchEvent(XBaseWindow.java:1106)
sun.awt.X11.XBaseWindow.dispatchToWindow(XBaseWindow.java:1066)
sun.awt.X11.XToolkit.dispatchEvent(XToolkit.java:565)
sun.awt.X11.XToolkit.run(XToolkit.java:674)
sun.awt.X11.XToolkit.run(XToolkit.java:595)
java.lang.Thread.run(Thread.java:722)



REPRODUCIBILITY :
This bug can be reproduced occasionally.