What is the JSF 2.0 code for handling user authentication?
<form method="POST" action="j_security_check">
    <table cellpadding="0" cellspacing="0" border="0">
         <tr>
            <td align="right">Username:&nbsp;</td>
            <td>
                <input type="text" name="j_username">
             </td>
         </tr>
         <tr>
             <td align="right">Password:&nbsp;</td>
             <td>
                <input type="password" name="j_password">
             </td>
         </tr>
         <tr>
             <td></td>
             <td>
                 <input type="submit" value="Login">
             </td>
        </tr>
    </table>
</form>

request.getUserPrincipal();

FacesContext.getCurrentInstance().getExternalContext().getUserPrincipal();