The main idea here is that your class exists only at the time of the html request. After processing the request, your class leaves.
State means that you “remember” things from one call to the next in class variables. Statelessness means that you do not.
Of course, you can save the class in the session and use it for each page, but I understand that this is not the situation that was discussed in the book.
EDIT:
ful , , , . , .