error 404 Spring Security 4.0 with primefaces

I'm using a web application with Spring, Spring Security, hibernate and primefaces. the probleme is about the authentication: when i don't create login page, Spring security creates one automatically and all work fine, but whene i create a login.xhtml page, i got this error: error 404 j_spring_security_check

the login.xhtml page:

<form action="j_spring_security_check" method="POST">
<fieldset>
    <legend>Connexion</legend>
    <p>
        <label>Login:</label>
        <input type="text" name="j_username"/>
    </p>
    <p>
        <label>Password:</label>
        <input type="password" name="j_password"/>
    </p>
    <br/>
        <input type="submit" value="Sign In"/>

    </fieldset>
</form>

My applicationContext.xml contains Spring security configuration is in Web-Inf folder, and the configuration is good. Can anyone help me ? please