Tomcat Servlet Container and Apache webserver

The main web server and the servlet container are different
programs, but the container runs within the address space of the main server as
a plug-in.

An example of this type is Tomcat running inside Apache Web Server. Apache
loads a JVM that runs Tomcat. In this case, the web server handles the static
content by itself, and Tomcat handles the servlets and JSP pages.