[ruby-dev:28121] post_connection_check with javacc.dev.java.net

ふと、https://javacc.dev.java.net/ を open-uri でアクセスすると、
post_connection_check でエラーになりました。

% ./ruby -v -ropen-uri -e 'URI("https://javacc.dev.java.net/").read'              
ruby 1.9.0 (2005-12-21) [i686-linux]
/home/akr/ruby/tmp-ruby/lib/ruby/1.9/net/http.rb:567: warning: using default DH parameters.
/home/akr/ruby/tmp-ruby/lib/ruby/1.9/openssl/ssl.rb:90:in `post_connection_check': hostname not match (OpenSSL::SSL::SSLError)
        from /home/akr/ruby/tmp-ruby/lib/ruby/1.9/open-uri.rb:291:in `open_http'
        from /home/akr/ruby/tmp-ruby/lib/ruby/1.9/net/http.rb:543:in `start'
        from /home/akr/ruby/tmp-ruby/lib/ruby/1.9/open-uri.rb:282:in `open_http'
        from /home/akr/ruby/tmp-ruby/lib/ruby/1.9/open-uri.rb:688:in `buffer_open'
        from /home/akr/ruby/tmp-ruby/lib/ruby/1.9/open-uri.rb:193:in `open_loop'
        from /home/akr/ruby/tmp-ruby/lib/ruby/1.9/open-uri.rb:191:in `open_loop'
        from /home/akr/ruby/tmp-ruby/lib/ruby/1.9/open-uri.rb:137:in `open_uri'
        from /home/akr/ruby/tmp-ruby/lib/ruby/1.9/open-uri.rb:590:in `open'
        from /home/akr/ruby/tmp-ruby/lib/ruby/1.9/open-uri.rb:598:in `read'
        from -e:1

Firefox でアクセスしても警告は出ないし鍵のマークも出るのです
が、これってどうしてエラーになるんでしょう?
-- 
[田中 哲][たなか あきら][Tanaka Akira]