public void verifyParam(String param, String name)
    throws BadParam {
    if (param == null) {
      throw new BadParam("Missing " + name + " parameter");
    }
  }
Verify that the parameter exists.  Throw an exception if invalid.
hcatalog/webhcat/svr/src/main/java/org/apache/hive/hcatalog/templeton/Server.java