WAR stands for Web Archive. jkl WAR-files are basically standard Java Archives (JAR), but with special structure, which make them suitable for distributing web applications, as per the servlet standard . Since JAR (and therefore, WAR), is compatible with the ZIP standard, you can extract JARs and WARs using any archiver that can handle ZIP files. Typical programs are 7-Zip , WinZip , InfoZip or pkzip . However, with Java JDK you get a special tool for handling JAR-files, which is called "jar". To extract a WAR-file, you could simply say jar -xvf JSPWiki.war Note how the jar syntax is very close to the UNIX "tar" -syntax :-). To create JAR files and WAR-files, the use of the "jar" tool is recommended. Otherwise some important files, such as the JAR manifest won't be included.