 <p>Probably its your own plugin that's locking the files. Try to implement a method/strategy to "release" them before attempting to delete. You can use Apache Commons IO to help you build/identifying this. Take a look at the <a href="http://commons.apache.org/io/api-release/org/apache/commons/io/FileDeleteStrategy.html" rel="nofollow">FileDeleteStrategy</a>. Also check the "FORCE" option.</p>