Java constants should work even when beginning with underscores (patc…

…h from David Corbin - dcorbin@machturtle.com)

git-svn-id: http://svn.codehaus.org/jruby/trunk/jruby@1450 961051c9-f516-0410-bf72-c9f7e237a7b7

src/builtin/javasupport.rb

@@ -48,7 +48,8 @@ class << self
     def valid_constant_name?(name)
       return false if name.empty?
       first_char = name[0..0]
-      return first_char == first_char.upcase
+      return (first_char == first_char.upcase && 
+              first_char != first_char.downcase)
     end
 
     def create_proxy_class(constant, java_class, mod)