Jar vs. War vs. Ear files

These files are simply zipped file (using java jar tool)

These files are created for different purposes.

.jar files

• contains the libraries, resources and accessories files like property files

.war files

• contains the web application that can be deployed on the any Servlet / JSP container
• contains jsp, html, javascript and other files for necessary for the development of web applications

.ear files 

• may contains multiple WARs and EJB modules of the application