lib/fast_blank.rb
class ::String # Explicitly undefine method before redefining to avoid Ruby warnings. undef_method(:blank?) if method_defined?(:blank?) end case RUBY_ENGINE when 'jruby' require 'fast_blank.jar' JRuby::Util.load_ext("com.headius.jruby.fast_blank.FastBlankLibrary") else require 'fast_blank.so' end