UsernamePasswordAuthenticationFilter – Looks for the username and password in the request and tries to authenticate if found these parameters in the request.
SecurityContextPersistenceFilter – Populates the SecurityContextHolder with information got from the configured.
ConcurrentSessionFilter – Filter for handling concurrent session.
DefaultLoginPageGeneratingFilter –Generates a login page for you, if you don’t explicitly disable that feature.
addFilter: This adds a custom Spring Security filter anywhere in the filter chain
addFilterBefore: This adds a custom filter before an existing specified filter class in the chain
addFilterAfter: This adds a custom filter after an existing specified filter class in the chain
addFilterAt: This adds a custom filter at the location of an existing specified filter class in the chain
https://www.javadevjournal.com/spring-security/registration-with-spring-security/