[keycloak-user] Programmatically login as a user

Hi, I have web application login via Keycloak working fine. But for a background processing like reading messages from a queue, need to login as a dedicated queue user behind the scenes. For this we can't redirect to login page. Earlier it was done pro grammatically by using JAAS login context and passing login module & credentials. Now when we switch to KC, what is the appropriate model to do this? Please advice! Thanks!