Creating static methods for handling common servlet request and transaction operations

Question

Consider these static methods outside of any servlet. All of them retrieve a hibernate session from a servlet filter.

public static User findUser(HttpServletRequest request) {
    Session session = (Session)request.getAttribute("session"); // org.hibernate.Session
    User user = (User)session.createQuery("from User u where u.email like :email and u.password like :password").setParameter("email", request.getParameter("email")).setParameter("password", hash(request.getParameter("password"))).uniqueResult();
    return user;
}

public static User userExist(HttpServletRequest request) {
    Session session = (Session)request.getAttribute("session"); // org.hibernate.Session
    User user = (User)session.createQuery("from User u where u.email like :email").setParameter("email", request.getParameter("email")).uniqueResult();
    return user;
}

public static User loadUser(HttpServletRequest request) {
    Session session = (Session)request.getAttribute("session"); // org.hibernate.Session
    User user = session.load(User.class, (long)request.getSession().getAttribute("userid"));
    return user;
}

public static boolean existReservations(HttpServletRequest request, boolean checkCurrent) {
    Date checkInDate = getDate(request.getParameter("checkInDate"));
    Date checkOutDate = getDate(request.getParameter("checkOutDate"));
    List<Reservation> res = loadUser(request).getReservations();
    for (Reservation r : res) {
        if (checkInDate.compareTo(r.getCheckOutDate()) <= 0 && checkOutDate.compareTo(r.getCheckInDate()) >= 0) {
            if (checkCurrent && r.getReservationID() != Long.parseLong(request.getParameter("id"))) {
                continue;
            }
            return true;                
        }
    }
    return false;
}

I will have to call these methods lots of times so they are in a Utils class. Now, I am absolutely sure that I will always call them if:

I'm in a servlet.
A hibernate session is open
A HTTPSession and a "userid" attribute is available.
In case of reservation methods, a parameter "id" is available

Now I found that doing this made my servlet code shorter. I personally think there are no problems doing this, I'm not modifying any attributes or parameters in HTTPServletRequest. I've seen many question asking if this is possible. But is this bad practice or I'm doing just fine? Are there cases where doing this approach make bad things happen?

I could see this being problematic if you used static _variables_ in these methods, since you'd lose concurrency protection. Since everything appears to be provided through the parameter(s), you should be OK. — T.D. Smith, Sep 17 '15 at 05:10
Separating common functions in utility classes is a good idea. however you ll soon end up with multiple threads messing up with your data. Two approach 1) use synchronized keyword inside you utility method to make method local variable thread safe 2) It is not a good practice to access session & request objects in a method without receiving them in `final` type reference variable. Take out important field from these object and pass it on to a thread safe static method. Refer these [link1](http://stackoverflow.com/questions/13910976/how-to-ensure-thread-safety-of-utility-static-method) — Jor El, Sep 17 '15 at 05:24
I typically create a root servlet in my project that all my servlets inherit from and put these classes in there. Then you can just call the methods in each servlet to the parent methods. — markbernard, Sep 17 '15 at 14:26

Creating static methods for handling common servlet request and transaction operations

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