@Override
    public boolean registerAuthenticationHandler(final AuthenticationHandler handler) {
        return registerAuthenticationHandlerWithPrincipalResolver(handler, null);
    }
This is {@link DefaultAuthenticationEventExecutionPlan}.

@author Misagh Moayyed
@since 5.1.0
core/cas-server-core-authentication-api/src/main/java/org/apereo/cas/authentication/DefaultAuthenticationEventExecutionPlan.java