code: public static void checkNullListArgument(List<?> list, String variableName) {
      // TODO (jhl388): Write a unit test for this method.
      if (null == list) {
        throw new NullPointerException(ExceptionMessageMap.getMessage("000005")
            + "  { variableName=[" + variableName + "] }");
      }
      if (list.size() == 0) {
        throw new IllegalArgumentException(ExceptionMessageMap.getMessage("000005")
            + "  { variableName=[" + variableName + "] }");
      }
      for (int i = 0; i < list.size(); i++) {
        checkNullArgument(list.get(i), variableName);
      }
    }
docs: Checks a <code>List&lt;?&gt;</code> argument to make sure it is not null, has length > 0, and
  none of its elements are null. If the <code>List&lt;?&gt;</code> or any contained instance is
  null, a <code>NullPointerException</code> is thrown. If the <code>List&lt;?&gt;</code> or
  any contained instance has length zero, an <code>IllegalArgumentException</code> is thrown.
  
  @param list
  The list to check.
  @param variableName
  The name of the variable being checked; for use in exception messages.