What is the difference between Application server and web server?

Application Server	Web Server
Application Server supports distributed transaction and EJB.	While Web Server only supports Servlets and JSP.
In order to run EJB or host enterprise Java application (.ear) file you need an application servers like JBoss, WebLogic, WebSphere or Glassfish	while you can still run your servlet and JSP or java web application (.war) file inside any web server like Tomcat or Jetty.
Application server provides support to web service and expose business level service e.g. EJB	web server is supposed to provide http protocol level service
Application server are more heavy than web server in terms of resource utilization.	Web server are not heavy in terms of resource utilization.