War -
distribute Java-based web applications. A WAR has the same file structure as a JAR file, which is a single compressed file that contains multiple files bundled inside it.
Jar -
The .jar files contain libraries, resources and accessories files like property files.
WAR files are used to combine JSPs, servlets, Java class files, XML files, javascript libraries, JAR libraries, static web pages, and any other resources needed to run the application.