Tomcat is a servlet container developed under the Jakarta Project at the Apache Software Foundation. Tomcat is an implementation of the Servlet and the JavaServer Pages (JSP) specifications from Sun Microsystems.
Tomcat runs with any web server that supports servlets and JSPs. Tomcat comes with the Jasper compiler that compiles JSPs into servlets. Tomcat servlet engine on Apache webserver is an often used combination. Tomcat is also an independent web server in itself and is used in development environments where there are no requirements for speed and transaction handling. Since Tomcat is written in Java, it runs on any operating system that has a JVM.
Tomcat is being developed and maintained by members of the Apache Software Foundation and independent volunteers. The source code and binary form of Tomcat is free under the Apache Software Licence. Tomcat 4.x is the latest production quality release, and it implements the Servlet 2.4 and JSP 2.0 specifications. As of version 4.x, Jakarta Tomcat uses the Catalina servlet container. Tomcat 5.x is still under development.
Following are the details of the directory hierarchy of a Tomcat installation :