See http://jira.codehaus.org/browse/JRUBY-4680

gistfile2.txt

[system]:test[git:master] $ jruby -v test_jruby_4680.rb 
jruby 1.6.0.dev (ruby 1.8.7 patchlevel 249) (2010-04-24 142fc60) (Java HotSpot(TM) 64-Bit Server VM 1.6.0_17) [x86_64-java]
Loaded suite test_jruby_4680
Started
F..F
Finished in 0.115 seconds.

  1) Failure:
test_method_selection_float1(TestMethodSelection) [test_jruby_4680.rb:12]:
<"float"> expected but was
<"integer">.

  2) Failure:
test_method_selection_integer2(TestMethodSelection) [test_jruby_4680.rb:16]:
<"integer"> expected but was
<"float">.

4 tests, 4 assertions, 2 failures, 0 errors

JRuby4680.java

public class JRuby4680 {
    public static String foo1(Integer arg) {
        return "integer";
    }
    
    public static String foo1(Float arg) {
        return "float";
    }
    
    public static String foo2(Object o, Integer arg) {
        return "integer";
    }
    
    public static String foo2(Object o, Float arg) {
        return "float";
    }
}

test_jruby_4680.rb

require 'java'
require 'test/unit'

java_import 'JRuby4680'

class TestMethodSelection < Test::Unit::TestCase
  def test_method_selection_integer1
    assert_equal "integer", JRuby4680.foo1(0x531)
  end
  
  def test_method_selection_float1
    assert_equal "float",   JRuby4680.foo1(1.532)
  end
  
  def test_method_selection_integer2
    assert_equal "integer", JRuby4680.foo2(Object.new, 0x531)
  end
  
  def test_method_selection_float2
    assert_equal "float",   JRuby4680.foo2(Object.new, 1.532)
  end
end