code: @Nonnull
      public static <T> T checkNotNull(T object, @Nonnull String message) {
          if (object == null) {
              throw new NullPointerException(message);
          }
          return object;
      }
docs: check for null and throw NullPointerException if null
  
  @param object
  reference to check
  @param message
  message for the illegal argument exception
  @param <T>
  reference type
  @return the input reference if not null
  @throws NullPointerException
  if object is null