# Engine java threads daemon type?

**URL:** <https://discuss.elastic.co/t/engine-java-threads-daemon-type/8954>\
**Category:** Elasticsearch\
**Created:** [September 7, 2012, 2:46pm UTC](https://discuss.elastic.co/t/engine-java-threads-daemon-type/8954 "2012-09-07T14:46:33Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![BillyEm](https://avatars.discourse-cdn.com/v4/letter/b/c4cdca/32.png) [@BillyEm](https://discuss.elastic.co/u/BillyEm)\
**Post date:** [September 7, 2012, 2:46pm UTC](https://discuss.elastic.co/t/engine-java-threads-daemon-type/8954/1 "2012-09-07T14:46:33Z")

</div>

Of the threads created at startup ... do they run with daemon flag set?  
Such that they will restart in case of a thread exception.

And speaking of that, will an exception be caught and logged in elastic  
logs, or lower? Does Lucene have neutrality or safety contract for the  
exposure runtime exceptions. Yeah that second one may be a dev list  
question?

I'm familiar with log4j use, but have seen solr escape stack traces with  
production settings. Just wanna be prepared.

thx in advance (tia)  
b

--

---

<div class="post-metadata">

**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, 3:13am UTC](https://discuss.elastic.co/t/engine-java-threads-daemon-type/8954/2 "2017-07-06T03:13:46Z")

</div>

Closed on July 6, 2017, 3:13am UTC