How to retrieve HttpSession from axis 2.0.

[snooze-g]

HI all.

I have a small problem with apache axis 2.0.
I have a web service like this

public class Login {
    
    
    
    public String userLogin(String username,
           String password) {

     

        return new String("username="+username.......);
    

}
}

I'm trying to get HttpSession from MessageContext but system return me NullPointerException.
Please help me.