# 1.5.5 ThreadDeath UncaughtExceptionHandler mystery

**URL:** <https://discuss.elastic.co/t/1-5-5-threaddeath-uncaughtexceptionhandler-mystery/36217>\
**Category:** Logstash\
**Created:** [December 2, 2015, 6:55pm UTC](https://discuss.elastic.co/t/1-5-5-threaddeath-uncaughtexceptionhandler-mystery/36217 "2015-12-02T18:55:24Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![bitsofinfo](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/bitsofinfo/32/459_2.png) [@bitsofinfo](https://discuss.elastic.co/u/bitsofinfo)\
**Post date:** [December 2, 2015, 6:55pm UTC](https://discuss.elastic.co/t/1-5-5-threaddeath-uncaughtexceptionhandler-mystery/36217/1 "2015-12-02T18:55:24Z")

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We just upgraded from 1.4.1 to 1.5.5.

Now we see these super-un-helpful errors in the error log every few minutes.

How can we get the root stack trace logged or possibly determine what is causing this???

`Exception: java.lang.ThreadDeath thrown from the UncaughtExceptionHandler in thread "Thread-28"`

Never got these errors previously prior to upgrade

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**Author:** ![bitsofinfo](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/bitsofinfo/32/459_2.png) [@bitsofinfo](https://discuss.elastic.co/u/bitsofinfo)\
**Post date:** [December 2, 2015, 7:27pm UTC](https://discuss.elastic.co/t/1-5-5-threaddeath-uncaughtexceptionhandler-mystery/36217/2 "2015-12-02T19:27:08Z")

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`--verbose` doesn't add anything more...

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**Author:** ![paltryeffort](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/paltryeffort/32/28717_2.png) [@paltryeffort](https://discuss.elastic.co/u/paltryeffort)\
**Post date:** [December 2, 2015, 9:01pm UTC](https://discuss.elastic.co/t/1-5-5-threaddeath-uncaughtexceptionhandler-mystery/36217/3 "2015-12-02T21:01:02Z")

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Running logstash with `--debug` produces a huge log file but without the error message. The file does not contain `ThreadDeath` or `UncaughtExceptionHandler`.  
The exception error message gets only printed to logstash.err without any further information.

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 6, 2017, 5:20am UTC](https://discuss.elastic.co/t/1-5-5-threaddeath-uncaughtexceptionhandler-mystery/36217/4 "2017-07-06T05:20:16Z")

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