Query Regarding Warning Messages in Logstash Version 8.12.0

Issue Description:
Upon upgrading to Logstash version 8.12.0, I have noticed the following warning messages appearing in the logs:

/usr/share/logstash/vendor/bundle/jruby/3.1.0/gems/concurrent-ruby-1.1.9/lib/concurrent-ruby/concurrent/executor/java_thread_pool_executor.rb:13: warning: method redefined; discarding old to_int
/usr/share/logstash/vendor/bundle/jruby/3.1.0/gems/concurrent-ruby-1.1.9/lib/concurrent-ruby/concurrent/executor/java_thread_pool_executor.rb:13: warning: method redefined; discarding old to_f
/usr/share/logstash/vendor/bundle/jruby/3.1.0/gems/nokogiri-1.15.5-java/lib/nokogiri/xml/node.rb:1007: warning: method redefined; discarding old attr


  • Logstash version: 8.12.0
  • JRuby version: jruby (3.1.4)
  • Installed logstash-core-plugin-api version: 2.1.28-java
  • Installed logstash-core version: 5.6.4-java
  • concurrent-ruby (1.1.9)

It is notable that these warnings are not present when using Logstash version 8.10.4. However, they started appearing after upgrading to version 8.12.0. I have attempted to isolate the issue by performing a clean installation without any additional plugins, but the warnings persist. Hence, I suspect that they may be related to the default plugins included in the Logstash 8.12.0 RPM package.

I would appreciate it if you could provide insight into the cause of these warning messages and any recommended steps to mitigate or resolve them. Additionally, if there are any known compatibility issues between Logstash version 8.12.0 and the dependencies mentioned above, I would like to understand them better.

1 Like

See this JRuby issue. It's not something elastic can fix and João confirms in that thread that with a recent JRuby snapshot logstash no longer logs those warnings.


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