policy.addPermission(new SecurityPermission("setPolicy"));
        Policy.setPolicy(savedPolicy);
      }
    }
  }

  /** Runs a runnable without any permissions. */
  public void runWithoutPermissions(Runnable r) {
    runWithPermissions(r);
  }

  /** A security policy where new permissions can be dynamically added or all cleared. */
  public static class AdjustablePolicy extends Policy {