I reported this on the puma/puma repo, but it probably belongs here.

I have a Rails 4.2.5.1 app running on Puma 2.16 on top of jRuby 1.7.23.
Everything works great there.

Everything else being the same, upgrading to jRuby 9.0.5.0 causes a strange issue.

Everything works fine, however, I will begin to see random thread exceptions (although more frequent the longer the app is running) when I use the rails send_data method.

Exception in thread "Ruby-0-Thread-44: /srv/www/reppro/shared/bundle/jruby/2.2.0/gems/puma-2.15.3-java/lib/puma/thread_pool.rb:61" IRReturnJump:<Static Type[1449297709]: local []:55>
Exception in thread "Ruby-0-Thread-54: /srv/www/reppro/shared/bundle/jruby/2.2.0/gems/puma-2.15.3-java/lib/puma/thread_pool.rb:61" IRReturnJump:<Static Type[594032292]: local []:55>

I would be more than happy to help triage this, just need some direction on what info you need.