code: public static void notNull(final Object obj, final String message) throws IllegalArgumentException {
          if (obj == null) {
              throw new IllegalArgumentException(message);
          }
      }
docs: Checks that object is not null, throws exception if it is.
  
  @param obj
  The object to check
  @param message
  The exception message
  
  @throws IllegalArgumentException
  Thrown if obj is null