# Logstash.runner Fatal error TypeError: illegal access on 'getThreadCount'

**URL:** <https://discuss.elastic.co/t/logstash-runner-fatal-error-typeerror-illegal-access-on-getthreadcount/116674>\
**Category:** Logstash\
**Created:** [January 23, 2018, 1:22pm UTC](https://discuss.elastic.co/t/logstash-runner-fatal-error-typeerror-illegal-access-on-getthreadcount/116674 "2018-01-23T13:22:31Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![sujalkpatel](https://avatars.discourse-cdn.com/v4/letter/s/c37758/32.png) [@sujalkpatel](https://discuss.elastic.co/u/sujalkpatel)\
**Post date:** [January 23, 2018, 1:22pm UTC](https://discuss.elastic.co/t/logstash-runner-fatal-error-typeerror-illegal-access-on-getthreadcount/116674/1 "2018-01-23T13:22:31Z")

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I am running LogStash for very first time. So I have no idea what's going on. Please help someone. I appreciate it in advance. Thank you.

`[2018-01-23T05:04:22,719][FATAL][logstash.runner] An unexpected error occurred! {:error=>#<TypeError: illegal access on 'getThreadCount': class org.jruby.javasupport.JavaMethod cannot access class sun.management.ThreadImpl (in module java.management) because module java.management does not export sun.management to unnamed module @4d3167f4>, :backtrace=>["/home/sujal/logstash-6.1.2/logstash-core/lib/logstash/instrument/periodic_poller/jvm.rb:80:in`collect\_threads\_metrics'", "/home/sujal/logstash-6.1.2/logstash-core/lib/logstash/instrument/periodic\_poller/jvm.rb:57:in `collect'", "/home/sujal/logstash-6.1.2/logstash-core/lib/logstash/instrument/periodic_poller/base.rb:57:in`start'", "org/jruby/RubyArray.java:2486:in `map'", "/home/sujal/logstash-6.1.2/logstash-core/lib/logstash/instrument/periodic_pollers.rb:23:in`start'", "/home/sujal/logstash-6.1.2/logstash-core/lib/logstash/agent.rb:419:in `configure_metrics_collectors'", "/home/sujal/logstash-6.1.2/logstash-core/lib/logstash/agent.rb:67:in`initialize'", "/home/sujal/logstash-6.1.2/logstash-core/lib/logstash/runner.rb:422:in `create_agent'", "/home/sujal/logstash-6.1.2/logstash-core/lib/logstash/runner.rb:333:in`execute'", "/home/sujal/logstash-6.1.2/vendor/bundle/jruby/2.3.0/gems/clamp-0.6.5/lib/clamp/command.rb:67:in `run'", "/home/sujal/logstash-6.1.2/logstash-core/lib/logstash/runner.rb:214:in`run'", "/home/sujal/logstash-6.1.2/vendor/bundle/jruby/2.3.0/gems/clamp-0.6.5/lib/clamp/command.rb:132:in `run'", "/home/sujal/logstash-6.1.2/lib/bootstrap/environment.rb:67:in`'"]}`

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<div class="post-metadata">

**Author:** ![robert-pda](https://avatars.discourse-cdn.com/v4/letter/r/4da419/32.png) [@robert-pda](https://discuss.elastic.co/u/robert-pda)\
**Post date:** [January 29, 2018, 10:52pm UTC](https://discuss.elastic.co/t/logstash-runner-fatal-error-typeerror-illegal-access-on-getthreadcount/116674/2 "2018-01-29T22:52:31Z")

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I'm having the same problem. Just installed on Linux (Linux Mint)

[2018-01-29T13:38:25,078]**[FATAL][logstash.runner] An unexpected error occurred! {:error=\>#\<TypeError: illegal access on 'getThreadCount': class org.jruby.javasupport.JavaMethod cannot access class sun.management.ThreadImpl (in module java.management) because module java.management does not export sun.management to unnamed module** @cb0ed20\>, :backtrace=\>["/usr/share/logstash/logstash-core/lib/logstash/instrument/periodic\_poller/jvm.rb:80:in `collect_threads_metrics'", "/usr/share/logstash/logstash-core/lib/logstash/instrument/periodic_poller/jvm.rb:57:in`collect'", "/usr/share/logstash/logstash-core/lib/logstash/instrument/periodic\_poller/base.rb:57:in `start'", "org/jruby/RubyArray.java:2486:in`map'", "/usr/share/logstash/logstash-core/lib/logstash/instrument/periodic\_pollers.rb:23:in `start'", "/usr/share/logstash/logstash-core/lib/logstash/agent.rb:419:in`configure\_metrics\_collectors'", "/usr/share/logstash/logstash-core/lib/logstash/agent.rb:67:in `initialize'", "/usr/share/logstash/logstash-core/lib/logstash/runner.rb:422:in`create\_agent'", "/usr/share/logstash/logstash-core/lib/logstash/runner.rb:333:in `execute'", "/usr/share/logstash/vendor/bundle/jruby/2.3.0/gems/clamp-0.6.5/lib/clamp/command.rb:67:in`run'", "/usr/share/logstash/logstash-core/lib/logstash/runner.rb:214:in `run'", "/usr/share/logstash/vendor/bundle/jruby/2.3.0/gems/clamp-0.6.5/lib/clamp/command.rb:132:in`run'", "/usr/share/logstash/lib/bootstrap/environment.rb:67:in `'"]}

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<div class="post-metadata">

**Author:** ![robert-pda](https://avatars.discourse-cdn.com/v4/letter/r/4da419/32.png) [@robert-pda](https://discuss.elastic.co/u/robert-pda)\
**Post date:** [January 29, 2018, 11:14pm UTC](https://discuss.elastic.co/t/logstash-runner-fatal-error-typeerror-illegal-access-on-getthreadcount/116674/3 "2018-01-29T23:14:49Z")

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This was the problem ..... "Logstash requires Java 8. Java 9 is not supported."

installed java8:  
_apt install openjdk-8-jre openjdk-8-jre-headless openjdk-8-jdk_

then checked what I had installed:  
_update-java-alternatives --list_

then set the default to java8:  
_update-java-alternatives --set /usr/lib/jvm/java-1.8.0-openjdk-amd64_

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<div class="post-metadata">

**Author:** ![sujalkpatel](https://avatars.discourse-cdn.com/v4/letter/s/c37758/32.png) [@sujalkpatel](https://discuss.elastic.co/u/sujalkpatel)\
**Post date:** [January 30, 2018, 8:49am UTC](https://discuss.elastic.co/t/logstash-runner-fatal-error-typeerror-illegal-access-on-getthreadcount/116674/4 "2018-01-30T08:49:29Z")

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Thanks Robert for pointing this out!

I actually found somewhere that Logstash doesn't work with JDK9 yet. So I downgraded it and it has been working since then.

Thanks anyway. It's the solution indeed.

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<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:** [February 27, 2018, 8:49am UTC](https://discuss.elastic.co/t/logstash-runner-fatal-error-typeerror-illegal-access-on-getthreadcount/116674/5 "2018-02-27T08:49:47Z")

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