def download_jruby(jruby_version, force=false)
      dist = "#{Dir.home}/.jruby-jar"
      unless force || (File.exists?("#{dist}/jruby-complete-#{jruby_version}.jar") && File.size("#{dist}/jruby-complete-#{jruby_version}.jar") > 0)
        mkdir_p dist
        base_dir = Dir.pwd
        cd dist
        $stderr.puts "JRuby complete jar not found. Downloading... (May take awhile)"
        download(jruby_version)
        cd base_dir
      end
    end
def download_jruby(jruby_version, force=false)
      dist = "#{Dir.home}/.jruby-jar"
      unless force || (File.exists?("#{dist}/jruby-complete-#{jruby_version}.jar") && File.size("#{dist}/jruby-complete-#{jruby_version}.jar") > 0)
        mkdir_p dist
        base_dir = Dir.pwd
        cd dist
        $stderr.puts "JRuby complete jar not found. Downloading... (May take awhile)"
        download(jruby_version)
        cd base_dir
      end
    end
Downloads the jruby-complete jar file for `jruby_version` and save in
 ~/.jruby-jar/jruby-complete.jar unless it already exits. If the jar is
 corrupt or an older version, set force to true to delete and re-download