diffzips.pl produces a "useful" diff between two ZIP files, helping to view what changed in between. It even adds a diff between different ZIP/JAR files inside both ZIP files.
First aim is to make sure all changes are mastered when deploying a new WAR file in production (helps spot what bugfixes/features are actually in the new WAR file).
Example output (with a patched colordiff for subdiffs coloring):
E.g. main.jsp and WEB-INF/lib/foo.jar have changed, and Bar.class and Qux.class are the changes inside WEB-INF/lib/foo.jar.
You may download diffzips.pl then.