i cannot see the different between using atmosphere api or use grizzly directly? can explain?
A:
Atmosphere API allows you to move from one web server to another. So, if you find out grizzly isn't it for you, then you can take your application to Tomcat AIO, JBoss, etc. Right now, I believe it is built on top of Grizzly and Jersey and it only supports Grizzly, but the intention is that it will eventually allow you to use whatever web server you want without the need for changing your configuration / recompiling your project.