# Grok for parsing java Log

**URL:** https://discuss.elastic.co/t/grok-for-parsing-java-log/43718
**Category:** Logstash
**Created:** [March 8, 2016, 12:32am UTC](https://discuss.elastic.co/t/grok-for-parsing-java-log/43718 "2016-03-08T00:32:35Z")
**Posts on this page:** 1
**Showing post:** 7

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### Author: ![sankallada](https://avatars.discourse-cdn.com/v4/letter/s/439d5e/32.png) [@sankallada](https://discuss.elastic.co/u/sankallada)
#### Post date: [March 9, 2016, 9:12pm UTC](https://discuss.elastic.co/t/grok-for-parsing-java-log/43718/7 "2016-03-09T21:12:19Z")

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@magnusbaeck I have a few layman question about Grok expressions

1. "while building complex grok expressions with multiple patterns, if any one of them fails for some reason (Eg: a match not found, say for example "%{TIMESTAMP\_ISO8601:timestamp}\s+%{LOGLEVEL1:loglevel}\s+" if log level fails then) I assume that the current line which is groked will be ignored, I'm I correct? I got this feeling while testing my patterns in grok debugger.

Thanks and Regards,  
Santhosh

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