bar.rb

class Bar
end

foo.rb

puts "QUE CHIDOOO"

class Foo
end

Main.java

import org.jruby.*;

/*
 The use case I have:

  -  Create a JRuby runtime
  -  Load a gem on it .. actually that gem ("buildr") requires many other gems and takes a lot of time to get them loaded (about 2secs)
  - Use that preloaded runtime to create clones 
  - Load a buildfile on that clone, without affecting the original runtime
  - drop the used cloned runtime, 

  - Use the preloaded runtiem to create another clone next time we run.
*/
public class Main {

    public static void main(String[] args) {
        Ruby one = Ruby.newInstance();
        one.getLoadService().require("foo");
        
        System.out.println("one.FOO = "+one.getObject().const_defined_p(one.getCurrentContext(), one.newSymbol("Foo")));

        Ruby two =(Ruby) one.clone();
        two.getLoadService().require("bar");
        System.out.println("two.FOO = "+two.getObject().const_defined_p(two.getCurrentContext(), two.newSymbol("Foo")));

        System.out.println("one.BAR = "+one.getObject().const_defined_p(one.getCurrentContext(), one.newSymbol("Bar")));
    }

}

main.rb

require 'jruby'

one = org.jruby.Ruby.newInstance
one.load_service.require 'foo'
p one.getObject.const_defined?(:Foo)

p one.java_object.dup
two = one
p two.getObject.const_defined?(:Foo)

one.load_service.require 'bar'

p one.getObject.const_defined?(:Bar)
p two.getObject.const_defined?(:Bar)