Pegando dados de um formulário com Vraptor

<form style="margin-top: 50px;" method="post" 
action="${linkTo[LoginController].login }">

				<div class="form-group">
					<input type="text" class="form-control" name="professor.nome"
						placeholder="Nome">
				</div>

				<div class="form-group">
					<input type="password" class="form-control" name="professor.senha"
						placeholder="Senha">
				</div>

				<div class="form-group">
					<input type="submit" class="btn btn-success btn-block" value="Entrar">
				</div>
			</form>

package br.com.marvin.reserva.controllers;

import br.com.caelum.vraptor.Controller;
import br.com.caelum.vraptor.Post;
import br.com.marvin.reserva.model.Professor;

@Controller
public class LoginController {
    @Post
    public void login(Professor professor) {
        //Executa algo
        // Porém, professor == null
    }
}