A Ratpack example showing the consequences of writing blocking code on the main thread.
Included is a JMeter test that sends 100 concurrent requests to 2 different handlers. Each handler's code sleeps for 10 seconds but one is blocking and the other is not. Run the test and see what the results are for yourself.
Accompanies this blog post http://blog.anacoders.com/blocking-code-in-ratpack/