Tomcat is known most popular open-source Java server, you can easily deploy in any server or a Linux machine. While we need to pay for licensing for IIS to deploy on a windows machine.
Deploying an internet server isn’t a one step deal. You would need to install a couple of servers that handle different aspects of a web server. The first one that you would need to install is the HTTP server. IIS (Internet Information Services) is a web server developed by Microsoft and a good choice for most people who are already comfortable with using Windows. Tomcat is another server, but it isn’t meant to process HTML documents, it is intended to run Java and JSP applications. The tomcat was developed by Apache as a Java/JSP server. It is developed primarily to communicate with Apache’s own web server but it is also compatible with IIS or any other web server available.