Using findjobj in R2013a

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Daniel Shub
Daniel Shub on 27 Sep 2013
Commented: Daniel Shub on 16 Oct 2013
I am trying to use Yair's FEX:findjobj in R2013a on Linux to basically do what he did in his blog post
desktop = com.mathworks.mde.desk.MLDesktop.getInstance;
jEditor = desktop.getGroupContainer('Editor').getTopLevelAncestor;
jEditor.findjobj
This causes MATLAB to become unresponsive and basically hang. I unfortunately don't have any other versions of MATLAB currently. Can anyone reproduce this?

Accepted Answer

Daniel Shub
Daniel Shub on 16 Oct 2013
I did a little profiling and found the problem. The findobj function calls home to the FEX and checks for a newer version in the checkVersion subfunction. On my system this fails because urlread times out (which takes a long time). The checkVersion subfunction catches the error and then discards it, which makes it tough to figure out what is going on. Using the undocumented feature of findobj
addpref('FindJObj','dontCheckNewerVersion', true)
stops from calling home and avoids the problems. I wonder if an error on trying to check the newer version should automatically set the preference to not check for updates.

More Answers (2)

per isakson
per isakson on 27 Sep 2013
Edited: per isakson on 27 Sep 2013
It seems to work fine here: R2013a, 64bit, Win7
>> desktop = com.mathworks.mde.desk.MLDesktop.getInstance;
jEditor = desktop.getGroupContainer('Editor').getTopLevelAncestor;
jEditor.findjobj
ans =
handle: 1-by-1620
>> version
ans =
8.1.0.604 (R2013a)
and the GUI is responsive
  1 Comment
Daniel Shub
Daniel Shub on 27 Sep 2013
Thanks. I wonder if it is Linux or my machine. Will have to keep searching.

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Yair Altman
Yair Altman on 5 Oct 2013
You only need to use findjobj without an output (result assignment) value if you want to see an interactive GUI display of all the objects in your analyzed object (in this case Desktop). If your Desktop contains numerous panels/windows/docked figures etc., then there might be so many descendant objects that it would take a long time (and large amounts of memory) to process, which might explain what you see.
If you only need findjobj to get the underlying reference of something, then assign a result (e.g., something=findjobj(...); ) and this should solve the issue. If you want to see the interactive GUI, then consider reducing your Desktop's complexity by closing some panels, or maybe start Matlab when it has access to more physical memory (to prevent virtual memory usage and thrashing).
  3 Comments
Daniel Shub
Daniel Shub on 16 Oct 2013
The hang happens in checkVersion. See my answer.

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