GPL or Ruby License?

[mv288]

At the end of this page http://json-jruby.rubyforge.org/

we see

JSON-JRuby, like json, is distributed under the Ruby license.

And in https://github.com/mernen/json-jruby

we see GPL license (https://github.com/mernen/json-jruby/blob/master/COPYING).

What is the correct license type?

[apotheon]

This is kind of an important issue. I, too, would like an answer.