What to do about "Exception in thread" java errors?

Recently, I was running some code when the following error was displayed to the command window:

Exception in thread "FileDecorationCache request queue" java.lang.
NullPointerException
  at com.mathworks.mlwidgets.explorer.model.table.UiFileList.fireListeners
(UiFileList.java:450)
  at com.mathworks.mlwidgets.explorer.model.table.UiFileList.
access$000(UiFileList.java:43)
  at com.mathworks.mlwidgets.explorer.model.table.UiFileList$1.
stateChanged(UiFileList.java:118)
  at com.mathworks.util.MulticastChangeListener.stateChanged
(MulticastChangeListener.java:26)
  at com.mathworks.mlwidgets.explorer.model.FileDecorationCache$1.
stateChanged(FileDecorationCache.java:101)
  at com.mathworks.util.MulticastChangeListener.stateChanged
(MulticastChangeListener.java:26)
  at com.mathworks.mlwidgets.explorer.model.FileDecorationModel$2$2.run
(FileDecorationModel.java:299)
  at com.mathworks.mlwidgets.explorer.extensions.matlab.H1Retriever.run
(H1Retriever.java:47)
  at com.mathworks.mlwidgets.explorer.model.FileDecorationModel$3$1.run
(FileDecorationModel.java:342)
  at com.mathworks.util.RequestQueue.execute(RequestQueue.java:105)
  at com.mathworks.util.RequestQueue.access$000(RequestQueue.java:23)
  at com.mathworks.util.RequestQueue$2.run(RequestQueue.java:76)
  at java.lang.Thread.run(Unknown Source)

My code continued running as normal, but I'm still concerned about this error. Does anyone have any suggestions on what I should do about it? I've seen similar (Java exception) errors in the past, and I think I've fixed some, but with this one I'm not even sure where to begin investigating. Generally, I've just ignored them and hoped they never pop up again, but I would prefer to not have to do that forever. I've tried googling for solutions, but I haven't found anything useful yet. Also, I've ran the same code a number of times and I've only seen this error once. Can anyone suggest an approach to handing Java exceptions?

Also, I should mention that I almost always see Java exception errors when I working with graphics or GUIs. The code the produced the above error is a GUI.

[Jessica Lam]

I also got that problem too. Any body help?

[Andreas]

Got the same Warning. Strange though: I've got an account bound license and the message appeared on 2 PCs.

[Charles]

I've been getting random Java exceptions like forever with Matlab. Just now, there was the NullPointerException in the FileDecorationCache request queue, and I found this thread when I searched on the web for the error.

Anyway, my only solution is to quit and restart Matlab. Continuing on isn't a good idea, mostly because the CPU usage usually becomes very high after such a Java exception, and the system becomes slow and unresponsive.