JRuby java.lang.ClassCastException - jruby

Question

I used a little Jruby script from http://www.javaworld.com/javaworld/jw-07-2006/jw-0717-ruby.html to test invokedynamic:
class ADuck
def quack()
puts "quack A";
end
end
class BDuck
def quack()
puts "quack B";
end
end
def quack_it(duck)
duck.quack
end
a = ADuck.new
b = BDuck.new
quack_it(a)
quack_it(b)
But when I compile in with JRuby to Java classfiles and then try to execute it I get the following exception:
Java HotSpot(TM) 64-Bit Server VM warning: Use -XX:+UnlockDiagnosticVMOptions be
fore EnableInvokeDynamic flag
Exception in thread "main" java.lang.ClassCastException: java.lang.Object cannot
be cast to java.lang.invoke.SwitchPoint
at org.jruby.runtime.invokedynamic.InvokeDynamicSupport.constantFallback
(InvokeDynamicSupport.java:659)
at duck_typing.__file__(duck_typing.rb:22)
at duck_typing.load(duck_typing.rb)
at duck_typing.main(duck_typing.rb)
My system: JDK 1.7.0_09 64bit on Windows 7 64bit, JRuby 1.7.2
Used commandlines:
jruby -Xcompile.invokedynamic=true -S jrubyc duck_typing.rb
java -XX:+UnlockExperimentalVMOptions -XX:+EnableInvokeDynamic -cp .;jruby-complete-1.7.2.jar duck_typing
A while ago I tested it on linux machine with same results and on Windows jdk8.
With JDK8 it worked, but gave me problems using the classfiles in another project.
Has anyone a idee how to fix it?
How can I use JRuby with indy on Java 7?

Answer 1

Except for the JRuby convenience parameter --server, all JVM runtime
parameters use the -J option, followed by the specific JVM setting.
For example:
Heap space settings: jruby -J-X
JRuby runtime settings: jruby -J-D
All the settings described in the following sections are JVM settings.
https://github.com/jruby/jruby/wiki/PerformanceTuning
try this instead
jruby -J-Xcompile.invokedynamic=true -S jrubyc duck_typing.rb