tool to visualise API differences between two JAR files

 Jardiff is a tool to help visualise API differences between two different
 versions of a project.
 .
 Jardiff takes two jar files and outputs all the public API changes as
 xml, html or plain text.
 .
 It can be used from command line or via an Apache Ant task.
 .
 It requires Java >= 1.4 to run.