code: public static void validateNotNull( Object obj, String objectName )
          throws NullArgumentException
      {
          if( obj == null )
          {
              throw new NullArgumentException( objectName + IS_NULL );
          }
      }
docs: Validates that the object <code>obj</code> is not null.
  
  @param obj        The object to be tested.
  @param objectName The name of the object, which is used to construct the exception message.
  
  @throws NullArgumentException if the stringToCheck is either null or zero characters long.