Hi there.

This is an issue with the MRI standard library. As such, please take up the issue to the core team. http://redmine.ruby-lang.org/

I'm not sure this is an issue with the MRI library -- the SocketError comes from JRuby's socket implementation :(

Anyway, I monkey-patched this one for myself by rescuing the SocketError when it could not bind.

jruby-1.7.9 :002 > require 'socket'
=> true
jruby-1.7.9 :003 > u = UDPSocket.new
=> #<UDPSocket:fd 616>
jruby-1.7.9 :004 > u2 = UDPSocket.new
=> #<UDPSocket:fd 617>
jruby-1.7.9 :005 > u.bind('0.0.0.0', 1100)
=> 0
jruby-1.7.9 :006 > u2.bind('0.0.0.0', 1100)
SocketError: bind: name or service not known
from org/jruby/ext/socket/RubyUDPSocket.java:160:in bind' from (irb):6:inevaluate'
from org/jruby/RubyKernel.java:1119:in eval' from org/jruby/RubyKernel.java:1519:inloop'
from org/jruby/RubyKernel.java:1282:in catch' from org/jruby/RubyKernel.java:1282:incatch'
from /Users/leeg/.rvm/rubies/jruby-1.7.9/bin/irb:13:in `(root)'