Difference between web-server and servlet container.

Question

What is the difference between "A Web Server" and "A Servlet Container"?
In general are all Web Servers Servlet(Web) Containers too or vice versa?

I have been using Apache Tomcat for JSP and Apache for PHP but unable to figure out the exact difference between those two, where exactly lies the difference?

I tried searching previous threads but could not find much.

Thanks! :-)

Answer 1

A Servlet Container is a Web Server that must be able to run Java Servlets.

Web Server, on the other hand, is a broader term including all software running and communicating through HTTP protocol.

Under these definitions:

1. All Servlet Containers are Web Servers
2. Not all Web Servers are Servlet Containers. I.E. Apache HTTP Server can not run Java Servlet directly.