* security manager. We require that any security manager permit getPolicy/setPolicy.
   */
  public void runWithPermissions(Runnable r, Permission... permissions) {
    SecurityManager sm = System.getSecurityManager();
    if (sm == null) {
      r.run();
      Policy savedPolicy = Policy.getPolicy();
      try {
        Policy.setPolicy(permissivePolicy());
        System.setSecurityManager(new SecurityManager());