User Authenication like Login over Frontend

Hi,
I have unfortunately no great experience in wordpress and the authentication methods. I would like to know whether the authentication on cookie has the same effect as the login on the wordpress front end.
My goal is to login a user from an external tomcat application in wordpress, because the blog function should be embedded in the tomcat application and the user should not log in twice.

is this possible?

Greetings
Bernhard