} finally {
        System.setSecurityManager(null);
        Policy.setPolicy(savedPolicy);
      }
    } else {
      Policy savedPolicy = Policy.getPolicy();
      AdjustablePolicy policy = new AdjustablePolicy(permissions);
      Policy.setPolicy(policy);

      try {
        r.run();
      } finally {
        policy.addPermission(new SecurityPermission("setPolicy"));