In AbstractWarDeployer there's some code that unpacks jars into the tmp directory.
This looks to be some limitation related to Tomcat not using the VFS from the comment
/* Unpack wars to the tmp directory for now until tomcat can use the vfs directly. Since * the vfs deals with the distinction between a true directory, the only way we can tell from * this level of the api is to look for a url that ends in '/'. Here we assume that the name is * the root url. */