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I see this error when open jnlp file via javaws manually: java.lang.AssertionError: Threading violation: not AppKit thread

Is there anything I can do with it?

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up vote 3 down vote accepted

Once I reverted back to the Apple provided java packages, it fixed my problems.

The article for this download is:

Update: Note that for some people, the Java 7 update works with Lantronix Spiders. I can confirm that a colleague with the same model Macbook Pro has no problems using the latest Java 7 update. Another with a Macbook Air experiences the same issue, which is also resolved by rolling back.

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Answers on Ask Different need to be more than just a link. It's okay to include a link, but please summarize or excerpt it in the answer. The idea is to make the answer stand alone. – Daniel Oct 30 '12 at 14:43
I've had the same problem with other KVM vendors... Seems they're very picky about the exact update of Java that you can have. – Brian Knoblauch Oct 30 '12 at 15:02
Super, thank you very much! – Samat Oct 31 '12 at 15:06
Remember to demand an update of your Latronix software from Latronix. – Thorbjørn Ravn Andersen Dec 15 '12 at 22:04

I found that on Lantronix Spider under Console settings, change "KVM Console Deployment" from "Web Start" to "Applet" and it worked again.

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For me it started worked like magic, without any changes – Samat Dec 16 '12 at 18:24

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