How to handle simultaneous logins? - spring

Question

In my webapp the login page is http://localhost:8080/vsingh/login
I am able to do below
Open tab1 and open the login page
Open tab2 and open the login page
In tab1 login with USER1. User is redirected to homepage. Now open tab2 and login with USER2. Now user is redirected to homepage of USER1.
How can I logout USER1 automatically in this case? Any pointers are appreciated.
PS: I do redirect automatically to homepage is user is already logged in and hits the login page, however in this case, the tab was already open before the user attempted login
#RequestMapping("/login")
public String login() {
Authentication auth = SecurityContextHolder.getContext().getAuthentication();
if (!(auth instanceof AnonymousAuthenticationToken) && auth != null) {
return "redirect:userHome";
}
return "login";
}
Spring Security XML
<http auto-config='true' use-expressions="true">
<intercept-url pattern="/*" access="permitAll" />
<access-denied-handler error-page="/login"/>
<form-login login-page="/login"
authentication-failure-handler-ref="customAuthFailureHandler"
username-parameter="username" password-parameter="password"
authentication-success-forward-url="/userHomeX" />
<csrf />
<logout logout-success-url="/logout" />
</http>
<authentication-manager>
<authentication-provider>
<password-encoder ref="encoder" />
<jdbc-user-service data-source-ref="dataSource"
users-by-username-query="SELECT USERNAME, RTRIM(PASSWORD) AS PASSWORD, CASE WHEN ENABLED=1 AND ADMIN_LOCK = 0 THEN 1 ELSE 0 END AS ENABLED FROM JWBDATABASE.JWBSCHEMA.USERS WHERE USERNAME=?"
authorities-by-username-query="SELECT USERNAME,USER_ROLE AS ROLE FROM JWBDATABASE.JWBSCHEMA.USERS WHERE USERNAME=?" />
</authentication-provider>
</authentication-manager>
<beans:bean id="encoder"
class="org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder">
<beans:constructor-arg name="strength" value="11" />
</beans:bean>
<beans:bean id="customAuthFailureHandler"
class="com.vj.authenticationManager.CustomAuthFailureHandler">
</beans:bean>
Why it is not duplicate?
Question is not about allowing multiple logins in different tabs but somehow force a single login for all tabs. If someone logins thru an already open login page with a different userid, either the old one should be forced logged out or throw an error on new login with some message