title: Check if password is valid in Keycloak from Spring Boot Application
body: <p>My user is already loggedin with a valid token, but in some important operations (like confirm or cancel of a paid subscription), I want it to send the password along the other data, so the server validate it.
  By now, my application has the users in a database, and it was easy to develop this way.</p>
  
  <p>How can I check that user sent password correctly? Will I need to try to login with the username and password in my backend?</p>