as already mentioned in #1813
there are plenty of cases where embedded jar files are NOT loaded which leads to errors later on - example of those jars are:

• lib/ruby/shared/json/ext/parser.jar
• lib/ruby/shared/jopenssl.jar
• lib/ruby/shared/kryptproviderjdk.jar

the error can be seen by (on jruby-1_7 and on master)
mvn clean install -Dinvoker.skip=false -Pjruby-jars
mvn clean install -Dinvoker.skip=false -Pmain