As Peter has noted, the technical term for "uncompressed WAR" is "exploded WAR". The
J2EE standard doesn't actually support exploded WARs, but many webapp servers either support them, explode WARs internally for their own convenience or both. JBoss uses the
Tomcat server for its
servlet and JSP functions, and Tomcat supports exploded WARs. The process involves creating a directory with the same name as the WAR file (minus the ".war" extension) and unzipping the WAR into that directory. Tomcat will then pick up on any updates to the files in that directory, although it's not an instant process since Tomcat detects changes via periodic scans of the WAR.
If you update certain files (such as web.xml), Tomcat will shutdown and restart the webapp. JSP updates simply cause a recompilation of the affected JSP.