gistfile1.txt

~/projects/jruby ➔ jirb
irb(main):001:0> class Object ; def blank?; length == 0; end; end                             
=> nil
irb(main):002:0> require 'java'
=> true
irb(main):003:0> a = java.util.ArrayList.new
=> []
irb(main):004:0> a << 1
=> [1]
irb(main):005:0> a.blank?
=> false