If you are planning to develop web application in Java. The Java EE technology used to develop web applications is Servlets. Servlets are java classes that process the web requests and deliver response to browser. Putting these classes directly in just JVM is not possible, nor it would start processing web requests. We need some server to receive the HTTP requests (HTTP is the protocol the browser and server talks in), convert it into an object oriented representation (from stream of bytes written on server socket into objects understandable by our java classes i.e. Servlet) and pass the request to our servlets. So that we don't have to deal with lower level details of network programming like programming HTTP protocol to receive the requests and sending response to user browser. But we could focus on building business logic of our projects. Tomcat Tomcat is a server that receive web requests over the network, converts them into refined object oriented representation and dispatch t...