code: private void setRWPermissions(File f) {
      if (!f.setReadable(true, false) || !f.setWritable(true, false)) {
        LOG.info("Could not set permissions for file : "
            + f + " probably because user : " + System.getProperty("user.name")
            + " is not the owner");
      }
    }
docs: Makes sure the given file has r/w permissions for everyone. We need this
  since the cache files might be accessed by different users on the
  same machine.