What is difference between TOMCAT server and BEA WEBLOGIC server
Tomcat is a Servlet/JSP container. It is free. It does not support the Java EE 6 container features such as EJB/JPA out of the box. These can be integrated but will not be equivalent to a proper EJB container.
WebLogic Server is a fully loaded EJB container. It has the best server and database connection pooling features in the market. It is easy to build/deploy/debug apps on Weblogic. It's a commercial product and quite expensive at that.