I fired up an application written in play framework with -Xms64m -Xmx100m and hit it with ab -n 500 -c 20 http://localhost:9000/ http://localhost:9000/ the RES

I fired up an application written in play framework with -Xms64m -Xmx100m and hit it with ab -n 500 -c 20 http://localhost:9000/ http://localhost:9000/ the RES column in top remained under 86m. The application does alot more than "hello world", I can speed it up and decrease memory consumption by substituting groovy based templates with java based templates using a module called japid. If you want to use JVM for hobbyist apps start using frameworks which are not based on j2ee.