Difference between EAR and WAR files
*.war file – this file is a composition of servlet class files. This package is HTTP request/response capable, can be accessed by a URL and can return a page. The contents are Java Classes, JSP files, GIF ( for website images ), and HTML files. Can be deployed on a Tomcat or Jetty servlet container.
*.ear file – this file is the composition of a enterprise application, that is composed of several war and ear files that functions as a single application. ear files are usually complete with HTTP request/response capability, Database access, Exposed API’s and other fucntionalities. EAR files are deployed on application servers such as Weblogic, JBoss or IBM Websphere. If you deploy a war file on application server, it is wrapped to an ear file, for standard deployment.
*.jar file – is the basic java archive file. A compilation of Java Classes that functions as a single application. May include Java Classes only.
Here are some more detailed answers on stackoverflow.com