Difference between tomcat , catalina and apache

Difference between tomcat , Catalina and Apache is as follows:

The Apache Web Server, often just called “Apache” or “httpd”, was developed in 1995 by Robert McCool and continuous development as well as maintenance is provided by the Apache Software Foundation. Known as the most popular web server.This is a huge accomplishment for a server that is an entirely an open-source project.

                The Apache Web Server is a C language implementation of an HTTP web server and can run a variety of features and modules to extend the core functionality.

• It is faster than Tomcat when serving static pages.

• Apache has more configuration options than Tomcat.

• Supports CGI scripts, Server API modules, Perl, PHP, etc

• It is more robust than Tomcat.

                   The big downside for Apache is the lack of functionality for Java Servlets or JavaServer Pages, which cannot be run with Apache’s web server. Tomcat was created to address this problem.

Apache Tomcat, otherwise known as “Tomcat” is an open-source web server that started as a servlet reference in 1999 and is developed and maintained by the Apache Software Foundation. It is a Java implementation that runs Java Servlets and JavaServer Pages, known as JSPs, as specified from Oracle. Often used together, Tomcat can be a valuable addition to your Apache Web Server installation; however, Tomcat can also stand on its own as a web server without Apache.

• Tomcat provides the Java Servlet and JSP support for dynamically served pages.

• Works as a light-weight testing server.

• Tomcat can be run in different modes to promote better performance

Tomcat is a Web Server that handles server side Java (in the form of Servlets and JSPs), and it's a part of the Apache Jakarta project group. Tomcat is the "reference" implementation of the Servlet and JSP standards - in other words, if it runs under Tomcat, it should run under any compliant Servlet / JSP container.

Catalina is Tomcat's servlet container. Catalina implements Sun Microsystems' specifications for servlet and JavaServer Pages (JSP). In Tomcat, a Realm element represents a "database" of usernames, passwords, and roles assigned to those users. Different implementations of Realm allow Catalina to be integrated into environments where such authentication information is already being created and maintained, and then use that information to implement Container Managed Security as described in the Servlet Specification..
                Catalina is the Java Engine (JRE / JVM) that's built into Tomcat and provides an environment in which Servlets can be run.