require 'socket'
Thread.new do
    begin
        server = TCPServer.new 3000
        while sock = server.accept
            sleep 10
            sock.close
        end
    rescue => e
        server.close
    end
end

long_string = "
JRuby is an implementation of the Ruby language using the JVM.

It aims to be a complete, correct and fast implementation of Ruby, at the same time as providing powerful new features such as concurrency without a global-interpreter-lock, true parallelism, and tight integration to the Java language to allow you to uses Java classes in your Ruby program and to allow JRuby to be embedded into a Java application.

You can use JRuby simply as a faster version of Ruby, you can use it to run Ruby on the JVM and access powerful JVM libraries such as highly tuned concurrency primitives, you can use it to embed Ruby as a scripting language in your Java program, or many other possibilites.
"

20.times do |i|
    begin
        s = TCPSocket.new 'localhost', 3000
        str = long_string.dup
        s.send str, 0
        str.clear
        # => JRUBY: RuntimeError: can't modify frozen string
        # => MRI: ""
    rescue => e
        puts "Test \##{i} raised an exception: #{e.message}"
    ensure
        s.close
    end
end