closed/java/awt/dnd/FileDialogDropTargetTest/FileDialogDropTargetTest.java sometimes failed on oracle unbreakable linux 6 with jdk 8, can't reproduce same issue on oel5.6, windows, solaris 10 sparc and with jdk 7 on same host

log:
----------System.out:(0/0)----------
----------System.err:(36/2307)----------
java.lang.ClassCastException: sun.awt.image.BufImgSurfaceData cannot be cast to sun.java2d.xr.XRSurfaceData
        at sun.java2d.xr.XRRenderer.validateSurface(XRRenderer.java:65)
        at sun.java2d.xr.XRRenderer.drawPath(XRRenderer.java:216)
        at sun.java2d.xr.XRRenderer.draw(XRRenderer.java:273)
        at sun.java2d.xr.XRRenderer.drawLine(XRRenderer.java:91)
        at sun.java2d.SunGraphics2D.drawLine(SunGraphics2D.java:2137)
        at sun.awt.X11.XScrollbar.paintArrows(XScrollbar.java:300)
        at sun.awt.X11.XScrollbar.paint(XScrollbar.java:236)
        at sun.awt.X11.XListPeer$ListPainter.paintScrollBar(XListPeer.java:1900)
        at sun.awt.X11.XListPeer$ListPainter.paintHorScrollbar(XListPeer.java:1913)
        at sun.awt.X11.XListPeer$ListPainter.paint(XListPeer.java:1814)
        at sun.awt.X11.XListPeer$ListPainter.access$000(XListPeer.java:1672)
        at sun.awt.X11.XListPeer.repaint(XListPeer.java:411)
        at sun.awt.X11.XListPeer.repaint(XListPeer.java:386)
        at sun.awt.X11.XListPeer.repaint(XListPeer.java:378)
        at sun.awt.X11.XListPeer.clear(XListPeer.java:1332)
        at sun.awt.X11.XListPeer.removeAll(XListPeer.java:222)
        at java.awt.List.clear(List.java:416)
        at sun.awt.X11.XFileDialogPeer.setFilterEntry(XFileDialogPeer.java:474)
        at sun.awt.X11.XFileDialogPeer.handleFilter(XFileDialogPeer.java:372)
        at sun.awt.X11.XFileDialogPeer.setDirectory(XFileDialogPeer.java:746)
        at sun.awt.X11.XFileDialogPeer.setVisible(XFileDialogPeer.java:780)
        at java.awt.Dialog.conditionalShow(Dialog.java:936)
        at java.awt.Dialog.show(Dialog.java:1038)
        at FileDialogDropTargetTest.main(FileDialogDropTargetTest.java:65)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:474)
        at com.sun.javatest.regtest.MainWrapper$MainThread.run(MainWrapper.java:96)
        at java.lang.Thread.run(Thread.java:722)

JavaTest Message: Test threw exception: java.lang.ClassCastException: sun.awt.image.BufImgSurfaceData cannot be cast to sun.java2d.xr.XRSurfaceData
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.lang.ClassCastException: sun.awt.image.BufImgSurfaceData cannot be cast to sun.java2d.xr.XRSurfaceData
result: Failed. Execution failed: `main' threw exception: java.lang.ClassCastException: sun.awt.image.BufImgSurfaceData cannot be cast to sun.java2d.xr.XRSurfaceData


test result: Failed. Execution failed: `main' threw exception: java.lang.ClassCastException: sun.awt.image.BufImgSurfaceData cannot be cast to sun.java2d.xr.XRSurfaceData

see comments for more details