Jython 2.7.1 released

Jython 2.7.1 was released last night; see the announcement for details.

I would like to update ImageJ and Fiji to use Jython 2.7.1 instead of 2.7.0 soon, since it contains lots of bug-fixes. For those impacted by this change: could you please test it? Here are the steps:

  • Download the jython-shaded-2.7.1-SNAPSHOT.jar.
  • Place it in your ImageJ installation’s jars/ folder.
  • Delete the old jars/jython-shaded-2.7.0.jar.
  • Start up ImageJ and try some Jython scripting.

If the feedback is positive, I will release and upload the 2.7.1-based Jython support tomorrow; if negative, I’ll investigate any problems. Thanks for testing!


Hi @ctrueden,

run some scripts, no issues so far!


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Hi Curtis,

it might be worth waiting a little, until the Jython developers know more about this one:



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Thanks for the heads up, @ehrenfeu, it looks like the culprit was identified, so now they just need to settle on the best way forward. I guess we need to wait to upgrade ImageJ until Jython 2.7.2, then.

It does not seem like there is a lot of movement beyond Jython 2.7.1 any time soon, nor any feasible solution to the performance issue discussed in the link above. So I have updated the pom-scijava bill of materials to reference jython-shaded 2.7.1 now, and it will roll out in the next Fiji update (probably within a couple of weeks). If it causes real problems for people, we can consider rolling back.

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