@WebServlet("/mvc")
public class ServletController extends HttpServlet{

@Override
protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    String parametro = request.getParameter("logica");
    String nomeDaClasse = "br.com.triadworks.todoList.logica." + parametro;

    try {
        Class classe = Class.forName(nomeDaClasse);
        Logica logica = (Logica) classe.newInstance();
        String pagina = logica.executa(request, response);
        request.getRequestDispatcher(pagina).forward(request, response);
    } catch (Exception e) {
        throw new ServletException("A lógica causou uma exceção!", e);
    }
}

public class AdicionaTarefa implements Logica {

@Override
public String executa(HttpServletRequest request, HttpServletResponse response) throws Exception {

    if (request.getSession().getAttribute("usuarioLogado") != null) {
        request.setAttribute("situacoes", Arrays.asList(Situacao.values()));
        return "WEB-INF/jsp/view/adiciona.jsp";
    }
    return "mvc?logica=TelaLogin";
}

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
        throws IOException, ServletException {

    HttpServletRequest httpServletRequest = (HttpServletRequest) request;
    HttpServletResponse servletResponse = (HttpServletResponse) response;
    HttpSession session = httpServletRequest.getSession();
}