Why Tomcat 7?

Apache Tomcat version 7.0 implements the Servlet 3.0 and JavaServer Pages 2.2 Specification.
Tomcat 7:
                1) Application memory leave and prevention.
                2) Support for external content directly into web application.
                3) lot of code cleanup for connectors and lifecycle.
                4) Full support of Java Servlet Specification 3.0.|
                5) Simplified embedding.

Tips for using tomcat:
                1) Use Shared library concepts.
                2) Custom error pages.
                3) Tweak memory settings.
                4) Use IP/Hostname filters to allow subset machines to connect.
                5) Secure directory listing.
                6) Use GZip compression.
Tomcat supports:
                      1) SSL.
                      2) Proxy support.
                      3) Load Balancer.
                      4) Virtual Hosting.
                      5) Logging.
                      6) SSI, CGI.
                      7) Embedded Tomcat.