JSF sayfa yönlendirmede hata

index sayfasında kalıyor profil'e geçmiyor

<h:commandbutton value="GİRİŞ" action="#{kullaniciBean.loginAction}"></h:commandbutton> <h:messages infostyle="color: green;" errorstyle="color: red;"/>

public void loginAction(){ String query = "SELECT kul_ad FROM kullanici WHERE kul_ad = '"+ kulAd +"' AND sifre = '"+ sifre +"' "; try{ Class.forName("com.mysql.jdbc.Driver"); con = DriverManager.getConnection(JDBC, UserName, password); statement = con.prepareStatement(query); resultSet = statement.executeQuery();

        if(resultSet.next()){
            onay = "tamam";
        }else{
            onay = "hata";
        }

        }catch (Exception e){
            e.printStackTrace();
        } finally {
            try {
                if (resultSet != null)
                    resultSet.close();
            } catch (SQLException ex) {
                ex.printStackTrace();
            }
            try {
                if (statement != null)
                    statement.close();
            } catch (SQLException ex) {
                ex.printStackTrace();
            }
            try {
                if (con != null)
                    con.close();
            } catch (SQLException ex) {
                ex.printStackTrace();
            }
        }
    System.out.println(onay);
    authentication();
}

public String authentication(){

    if(onay.equals("tamam")){
        System.out.println("1");
        return "/profil";
    }else{
        System.out.println("2");
        FacesContext context = FacesContext.getCurrentInstance();
        context.addMessage(null, new FacesMessage(FacesMessage.SEVERITY_ERROR, "Hatalı Giriş", null));
        return "/index";
    }

}

}