What is the difference between JAR and WAR?

Difference betwen JAR AND WAR

.jar files: These files are with the .jar extension. The .jar files contain the libraries, resources and accessories files like property files.

.war files: These files are with the .war extension. The war file contains the web application that can be deployed on the any servlet/jsp container. The .war file contains jsp, html, javascript and other files for necessary for the development of web applications.

Source:

http://forum.java.sun.com/thread.jspa?threadID=485823&messageID=2273976

The main difference between a JAR and a WAR is that a JAR is not really a single purpose format, while a WAR is. With a JAR file, you can package lots of different things. Usually you package up Java classes, but you could put pretty much anything into a JAR file, and you can create JARs that have whatever files and directory formats you want. For instance, Oracle (at least in 8.1.x) actually uses JAR files to distribute the Oracle software on the install CDs, and IBM uses them to distribute an installable version of the documentation for WebSphere. Technically you can put JSP pages, HTML pages, servlet classes, etc. in a JAR, but you generally don't -- you use a WAR.

WAR files are JAR files with a specific format. This format is defined in the servlet spec (which you can look at on the java.sun.com site). Essentially, the WAR file is a standard format for web applications that has specific directories and specific files. This includes a WEB-INF directory, a WEB-INF/web.xml file used to describe the application, a WEB-INF/lib directory for JAR files used by the application, and a WEB-INF/classes directory for class files that aren't distributed in a JAR. You would put the pages (JSPs and HTML) in the WAR as well. Then, you can distribute your application as one file, instead of as a collection of images, HTML pages, and Java classes.

Source:

http://www.theserverside.com/discussions/thread.tss?thread_id=10905

Message was edited by:

lochdsmile

lochdsmilea at 2007-7-9 5:08:59 >