Resin is the Java Application Server for high traffic sites that require speed and scalability. It is one of the earliest Java Application Servers, and has stood the test of time due to engineering prowess not marketing fluff and fads.
Resin 4 was the first Java EE Web Profile certified Java application server. Resin 4 was built from the ground up around Java Dependency Injection (CDI). Resin is over 13 years old, yet it has kept up with the times. Resin 4 has been optimized to work in cloud computing environments like Amazon EC2.
As a web developer you'll like it!
it's designed for makeing the life of the developer easy with fast-recompiling JSP pages and many other things which will improve your work
Only 25MB in size, starts up in 2 seconds or less, the complete Java EE 6 Web Profile, the home of the independent CDI implementation CanDI... what's there not to like? Highly recommended!