The Apache Tomcat software is an open source implementation of the Java Servlet, JavaServer Pages, Java Expression Language and Java WebSocket technologies.
Servlet
Java server side technology which will handle request and response. It doean’t understand HTTP it is just a middle layer.
JSP (Java server page)
Is a java Representationa layer instead of reular HTML file. used to write java code in HTML tags to dynamically represent data to user.
Components
Catalina
Catalina is Tomcat's servlet container. which handles the requests between the Servlet and the rest of tomacat (container) such as URLs routing to different Servlet
Coyote
Coyote is a Connector component for Tomcat that supports the HTTP 1.1 and 2 protocol as a web server. This allows Catalina, nominally a Java Servlet or JSP container, to also act as a plain web server that serves local files as HTTP documents. Allowing the server to serve static files
Jasper
Tomcat Architecture
Refrences