Minimal rails 6.1.1 application fails in tomcat with jruby 9.3.3.0

[jlahtinen]

Environment Information

• JRuby version (jruby -v) and command line (flags, JRUBY_OPTS, etc)
• Operating system and platform (e.g. uname -a)

jruby 9.3.3.0 (2.6.8) 2022-02-08 b26de1f5c5 OpenJDK 64-Bit Server VM 25.322-b06 on 1.8.0_322-b06 +jit [linux-x86_64]
Linux name 3.10.0-1160.31.1.el7.x86_64 #1 SMP Wed May 26 20:18:08 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
unmodified https://dlcdn.apache.org/tomcat/tomcat-8/v8.5.75/bin/apache-tomcat-8.5.75.zip
unmodified rails application created with rails new minimal --minimal
rails version 6.1.1

made war file using bundle exec warble. Moved minimal.war to unmodifed tomcat installation under /webapps. curled page http://localhost:8080/minimal.

Before bundle exec warble works. One workaround has to be made 😓. jruby/warbler#508

Making working war file for tomcat needs 2 modifications to META-INF/init.rb 😓 😓

• modify line ENV['RAILS_ENV'] ||= ENV_JAVA[ 'RAILS_ENV' ] || 'No value for 'env' found' to ENV['RAILS_ENV'] ||= ENV_JAVA[ 'RAILS_ENV' ] || 'production'
• add line Gem.paths = ENV before line require 'bundler/shared_helpers'

Expected Behavior

Rails root page should be visible

Actual Behavior

11-Feb-2022 15:03:27.332 SEVERE [http-nio-8080-exec-6] org.apache.catalina.core.StandardWrapperValve.invoke Servlet.service() for servlet [default] in context with path [/minimal] threw exception [Filter execution threw an exception] with root cause
        java.lang.LinkageError: loader constraint violation: when resolving method "org.jruby.runtime.Helpers.constructRubyStringArray(Lorg/jruby/RubyString;Lorg/jruby/RubyString;Lorg/jruby/RubyString;)[Lorg/jruby/RubyString;" the class loader (instance of <bootloader>) of the current class, java/lang/Object, and the class loader (instance of org/apache/catalina/loader/ParallelWebappClassLoader) for the method's defining class, org/jruby/runtime/Helpers, have different Class objects for the type org/jruby/RubyString used in the signature

[jimtng]

I'm experiencing a similar issue:

Caused by: java.lang.LinkageError: loader constraint violation: when resolving method 'org.jruby.RubyString[] org.jruby.runtime.Helpers.constructRubyStringArray(org.jruby.RubyString, org.jruby.RubyString, org.jruby.RubyString)' the class loader 'bootstrap' of the current class, java/lang/Object, and the class loader org.eclipse.osgi.internal.loader.EquinoxClassLoader @3b354d05 for the method's defining class, org/jruby/runtime/Helpers, have different Class objects for the type org/jruby/RubyString used in the signature (java.lang.Object is in module java.base of loader 'bootstrap'; org.jruby.runtime.Helpers is in unnamed module of loader org.eclipse.osgi.internal.loader.EquinoxClassLoader @3b354d05, parent loader java.net.URLClassLoader @9a7504c)
        at java.lang.invoke.MethodHandleNatives.resolve(Native Method) ~[?:?]
        at java.lang.invoke.MemberName$Factory.resolve(MemberName.java:1070) ~[?:?]
        at java.lang.invoke.MemberName$Factory.resolveOrFail(MemberName.java:1098) ~[?:?]
        at java.lang.invoke.MethodHandles$Lookup.resolveOrFail(MethodHandles.java:2030) ~[?:?]
        at java.lang.invoke.MethodHandles$Lookup.findStatic(MethodHandles.java:1102) ~[?:?]

jruby 9.3.3.0 embedded in an osgi bundle, Java 11. The issue doesn't happen when I started the whole application. It only happens when I updated the bundle to a newer version, triggering a bundle reload, which eventually leads to this error.