MATLAB: External monitor throws Java exception

guijavaMATLAB

When I connect/disconnect my external monitor, a Java exception appears on MATLAB's command line:
Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: sun.awt.image.BufImgSurfaceData cannot be cast to sun.java2d.xr.XRSurfaceData at sun.java2d.xr.XRPMBlitLoops.cacheToTmpSurface(XRPMBlitLoops.java:148) at sun.java2d.xr.XrSwToPMBlit.Blit(XRPMBlitLoops.java:356) at sun.java2d.pipe.DrawImage.blitSurfaceData(DrawImage.java:959) at sun.java2d.pipe.DrawImage.renderImageCopy(DrawImage.java:577) at sun.java2d.pipe.DrawImage.copyImage(DrawImage.java:67) at sun.java2d.pipe.DrawImage.copyImage(DrawImage.java:1014) at sun.java2d.pipe.ValidatePipe.copyImage(ValidatePipe.java:186) at sun.java2d.SunGraphics2D.drawImage(SunGraphics2D.java:3318) at sun.java2d.SunGraphics2D.drawImage(SunGraphics2D.java:3296) at javax.swing.ImageIcon.paintIcon(ImageIcon.java:425) at com.mathworks.toolstrip.plaf.GalleryButtonUI.paintContent(GalleryButtonUI.java:115) at com.mathworks.toolstrip.plaf.RegularButtonUI.paintContent(RegularButtonUI.java:64) at com.mathworks.toolstrip.plaf.ToolstripButtonUI.paint(ToolstripButtonUI.java:197) at javax.swing.plaf.ComponentUI.update(ComponentUI.java:161) at javax.swing.JComponent.paintComponent(JComponent.java:780) at com.mathworks.mwswing.MJButton.paintComponent(MJButton.java:430) at javax.swing.JComponent.paint(JComponent.java:1056) at com.mathworks.mwswing.MJButton.paint(MJButton.java:408) at javax.swing.JComponent.paintChildren(JComponent.java:889) at javax.swing.JComponent.paint(JComponent.java:1065) at javax.swing.JComponent.paintChildren(JComponent.java:889) at javax.swing.JComponent.paint(JComponent.java:1065) at javax.swing.JComponent.paintChildren(JComponent.java:889) at javax.swing.JComponent.paint(JComponent.java:1065) at javax.swing.JComponent.paintToOffscreen(JComponent.java:5210) at javax.swing.BufferStrategyPaintManager.paint(BufferStrategyPaintManager.java:290) at javax.swing.RepaintManager.paint(RepaintManager.java:1272) at javax.swing.JComponent._paintImmediately(JComponent.java:5158) at javax.swing.JComponent.paintImmediately(JComponent.java:4969) at javax.swing.RepaintManager$4.run(RepaintManager.java:831) at javax.swing.RepaintManager$4.run(RepaintManager.java:814) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80) at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:814) at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:789) at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:738) at javax.swing.RepaintManager.access$1200(RepaintManager.java:64) at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1732) at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311) at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756) at java.awt.EventQueue.access$500(EventQueue.java:97) at java.awt.EventQueue$3.run(EventQueue.java:709) at java.awt.EventQueue$3.run(EventQueue.java:703) at java.security.AccessController.doPrivileged(Native Method) at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80) at java.awt.EventQueue.dispatchEvent(EventQueue.java:726) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93) at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
I'm using MATLAB R2017b (fresh install) on Xubuntu 17.10. I'm invoking MATLAB via the command
LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libstdc++.so.6 /usr/local/MATLAB/R2017b/bin/matlab -desktop
Since this doesn't crash the MATLAB GUI, I don't consider it a critical issue, but it is annoying (and easily reproduced).
Edit: Arguably this does 'crash' the MATLAB GUI: subsequent keyboard input retriggers the same exception. My workaround, which I forgot to mention, is mouse-clicking the Clear Workspace button. I won't pretend to understand how this resolves the issue.

Best Answer

Seems like I've fixed my problem by disabling xrender by putting the line

-Dsun.java2d.xrender=false

in a new file called /usr/local/MATLAB/R2018a/bin/glnxa64/java.opts

Unintended consequences TBD.

Java options ref: https://www.mathworks.com/help/matlab/matlab_env/java-opts-file.html?s_tid=srchtitle

Similar bug: https://www.mathworks.com/matlabcentral/answers/381324-why-do-i-get-java-exception-on-display-change

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