The Tomcat server is the most widely used open source implementation of the Java Servlet, JavaServer Pages, Java Expression Language, and Java WebSocket technologies.

Apache Tomcat software powers numerous large-scale, mission-critical web applications across a diverse range of industries and organizations.
The sample TomCat application we will be using for this exercise is included in a git repository so that you can run through this tutorial easily.
In Tomcat, we have to move the war file to the CATALINA_BASE/webapps directory. Tomcat will then install it automatically and deploy the application for you.