JRuby become_java! ignoring java_package

Foo.rb

require 'jruby/core_ext'
require 'java'
java_package 'rxtest.foobar'

class Foo
  print "Heigh-ho!\n"

  def bar()
    puts "Called."
  end
end

Foo.become_java!("")

# Output
# % javap -classpath . rubyobj.Foo
# public class rubyobj.Foo extends org.jruby.RubyObject implements org.jruby.java.codegen.Reified {
#   public static void clinit(org.jruby.Ruby, org.jruby.RubyClass);
#   public rubyobj.Foo(org.jruby.Ruby, org.jruby.RubyClass);
#   public rubyobj.Foo();
#   public org.jruby.runtime.builtin.IRubyObject bar();
# }