Hi all,

Today I came across this exception and I'm not sure if it's related with JRuby or simple xml gem.

The backtrace is as follows:

[2012-07-23 11:57:38 +0000] -  INFO  jruby.rack: ThreadError - BUG: execRecursive called outside recursiveListOperation:
    org/jruby/RubyArray.java:1871:in `join'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/xml-simple-1.1.1/lib/xmlsimple.rb:866:in `value_to_xml'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/xml-simple-1.1.1/lib/xmlsimple.rb:854:in `value_to_xml'
    org/jruby/RubyArray.java:1615:in `each'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/xml-simple-1.1.1/lib/xmlsimple.rb:848:in `value_to_xml'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/xml-simple-1.1.1/lib/xmlsimple.rb:813:in `value_to_xml'
    org/jruby/RubyHash.java:1186:in `each'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/xml-simple-1.1.1/lib/xmlsimple.rb:797:in `value_to_xml'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/xml-simple-1.1.1/lib/xmlsimple.rb:813:in `value_to_xml'
    org/jruby/RubyHash.java:1186:in `each'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/xml-simple-1.1.1/lib/xmlsimple.rb:797:in `value_to_xml'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/xml-simple-1.1.1/lib/xmlsimple.rb:239:in `xml_out'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/xml-simple-1.1.1/lib/xmlsimple.rb:259:in `xml_out'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/lib/surechem/sinatra/helpers.rb:26:in `flush_data'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/lib/surechem/api/requests/export.rb:156:in `__file__'
    org/jruby/RubyMethod.java:117:in `call'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/sinatra-1.3.2/lib/sinatra/base.rb:1212:in `compile!'
    org/jruby/RubyProc.java:258:in `call'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/sinatra-1.3.2/lib/sinatra/base.rb:785:in `route!'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/sinatra-1.3.2/lib/sinatra/base.rb:801:in `route_eval'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/sinatra-1.3.2/lib/sinatra/base.rb:785:in `route!'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/sinatra-1.3.2/lib/sinatra/base.rb:822:in `process_route'
    org/jruby/RubyKernel.java:1197:in `catch'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/sinatra-1.3.2/lib/sinatra/base.rb:820:in `__ensure__'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/sinatra-1.3.2/lib/sinatra/base.rb:784:in `route!'
    org/jruby/RubyArray.java:1615:in `each'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/sinatra-1.3.2/lib/sinatra/base.rb:783:in `route_b_'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/sinatra-1.3.2/lib/sinatra/base.rb:886:in `dispatch_b_'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/newrelic_rpm-3.3.5/lib/new_relic/agent/instrumentation/sinatra.rb:46:in `dispatch_with_newrelic'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/newrelic_rpm-3.3.5/lib/new_relic/agent/instrumentation/controller_instrumentation.rb:257:in `perform_action_with_newrelic_trace'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/newrelic_rpm-3.3.5/lib/new_relic/agent/method_tracer.rb:242:in `__ensure__'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/newrelic_rpm-3.3.5/lib/new_relic/agent/method_tracer.rb:241:in `trace_execution_scoped'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/newrelic_rpm-3.3.5/lib/new_relic/agent/instrumentation/controller_instrumentation.rb:252:in `__ensure__'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/newrelic_rpm-3.3.5/lib/new_relic/agent/instrumentation/controller_instrumentation.rb:251:in `perform_action_with_newrelic_trace'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/newrelic_rpm-3.3.5/lib/new_relic/agent/instrumentation/sinatra.rb:43:in `dispatch_with_newrelic'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/sinatra-1.3.2/lib/sinatra/base.rb:719:in `call!'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/sinatra-1.3.2/lib/sinatra/base.rb:871:in `invoke'
    org/jruby/RubyKernel.java:1197:in `catch'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/sinatra-1.3.2/lib/sinatra/base.rb:871:in `invoke'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/sinatra-1.3.2/lib/sinatra/base.rb:719:in `call_b_'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/sinatra-1.3.2/lib/sinatra/base.rb:705:in `call'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/rack-1.4.1/lib/rack/session/abstract/id.rb:205:in `context'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/rack-1.4.1/lib/rack/session/abstract/id.rb:200:in `call'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/rack-1.4.1/lib/rack/logger.rb:15:in `call'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/rack-1.4.1/lib/rack/commonlogger.rb:20:in `call'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/rack-1.4.1/lib/rack/head.rb:9:in `call'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/rack-1.4.1/lib/rack/methodoverride.rb:21:in `call'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/sinatra-1.3.2/lib/sinatra/base.rb:1334:in `call'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/sinatra-1.3.2/lib/sinatra/base.rb:1416:in `synchronize'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/sinatra-1.3.2/lib/sinatra/base.rb:1334:in `call'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/rack-1.4.1/lib/rack/commonlogger.rb:20:in `call'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/rack-1.4.1/lib/rack/session/abstract/id.rb:205:in `context'
    /srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/rack-1.4.1/lib/rack/session/abstract/id.rb:200:in `call'
    file:/srv/surechem-api/releases/9d61b7d1e0bed8ef7de4185d3f4dd85c6211e1dc/vendor/bundle/jruby/1.9/gems/jruby-rack-1.1.6/lib/jruby-rack-1.1.6.jar!/rack/handler/servlet.rb:21:in `call'

Can anyone point me in the right direction?

Thank you.