programmatic authentication in JSF 2 brings auth pop-up

Question

For our web app (running on Websphere 8.5) we are using programmatic login using Basic HTTP authentication as suggested in (https://stackoverflow.com/a/2207147/2683081) i.e. Servlet 3.0 HttpServletRequest#login().

After I login using our application login page, I keep getting the 2nd log-on screen with a message

The server __ at Default Realm required username and password

Is there a way to avoid getting that standard Windows Security pop-up.

I tried to set response headers with Authorization but no luck.

Update:- Application is on Mojjaro JSF 2.1.28 on Websphere8.5 with LDAP Security

       <?xml version="1.0" encoding="UTF-8"?>
    <web-app version="3.0"
        xmlns="http://java.sun.com/xml/ns/javaee"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" >
      <display-name>TEST</display-name>
      <welcome-file-list>
        <welcome-file>index.jsf</welcome-file>
      </welcome-file-list>

      <!-- Spring -->
        <listener>
        <listener-class>
                org.springframework.web.context.request.RequestContextListener
            </listener-class>
      </listener>
      <listener>
        <listener-class>
                org.springframework.web.context.ContextLoaderListener
            </listener-class>
      </listener>
      <!-- end Spring-->
      <context-param>
            <param-name>javax.faces.INTERPRET_EMPTY_STRING_SUBMITTED_VALUES_AS_NULL</param-name>
            <param-value>true</param-value>
      </context-param>      
      <context-param>      
        <param-name>com.sun.faces.expressionFactory</param-name> 
        <param-value>org.jboss.el.ExpressionFactoryImpl</param-value>    
      </context-param> 
       <listener>
            <listener-class>com.sun.faces.config.ConfigureListener</listener-class>
       </listener>

       <context-param>
            <param-name>javax.faces.STATE_SAVING_METHOD</param-name>
            <param-value>server</param-value>
        </context-param>

        <context-param>
             <param-name>javax.faces.PARTIAL_STATE_SAVING</param-name>
             <param-value>false</param-value>
         </context-param>   
        <!-- Faces Servlet -->
        <servlet>
            <servlet-name>Faces Servlet</servlet-name>
            <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
            <load-on-startup>1</load-on-startup>
        </servlet>
        <servlet-mapping>
            <servlet-name>Faces Servlet</servlet-name>
            <url-pattern>*.jsf</url-pattern>
        </servlet-mapping>

        <context-param>
            <param-name>primefaces.THEME</param-name>
            <param-value>casablanca</param-value>
        </context-param>
<security-constraint>
        <display-name>constraint-0</display-name>
        <web-resource-collection>
            <web-resource-name>constraint-0</web-resource-name>
            <description/>
            <url-pattern>/test/*</url-pattern>
        </web-resource-collection>
        <auth-constraint>
            <description/>
            <role-name>admin</role-name>
            <role-name>guest</role-name>
        </auth-constraint>
    </security-constraint>
    <security-role>
    <role-name>admin</role-name>
    </security-role>
    <security-role>
    <role-name>guest</role-name>
    </security-role>
      <!-- Mime Mapping -->
        <mime-mapping>
        <extension>png</extension>
        <mime-type>image/png</mime-type>
        </mime-mapping>
    </web-app>

login.xhtml

<h:form id="login">                 
    <div class="inputlabel">
        <h:outputLabel for="username" value="Login:"/>
    </div>
    <div>
        <h:inputText value="#{loginBean.username}" id="username" size="25" />
    </div>
    <div class="inputlabel">
        <h:outputLabel for="password" value="Password:"/>
    </div>
    <div>
        <h:inputText value="#{loginBean.password}" id="password" size="25" />
    </div>
    <div>
        <h:commandButton action="#{loginBean.login}" value="Login" />
    </div>                  
</h:form>

LoginBean.java

public String login() throws IOException {
    FacesContext context = FacesContext.getCurrentInstance();
    ExternalContext externalContext = context.getExternalContext();
    HttpServletRequest request = (HttpServletRequest) externalContext.getRequest();
    try {       
        request.login(username, password);            
        return "/testing/index.jsf?faces-redirect=true";
    } catch (ServletException e) {       
        context.addMessage(null, new FacesMessage("Invalid login!!!"));        
    }
}