Session tracking does not persist

Question

Here is my code. The HttpSession we used was also used in class and it worked but doesn't work now. And I cannot print anything after the for loop. I use doGet() method. We need to store the stringToPhone in a session object and the carrierNum to a cookie.

    String carrier = request.getParameter("carrier");
    String carrierNum = request.getParameter("carrierNum");
    String stringToPhone = request.getParameter("phoneNumber");
    String equiPhoNum = "";

    PrintWriter out = response.getWriter();
    HttpSession s1 = request.getSession();

    out.println("Carrier: " + carrier);
    out.println("Inputted phone number: " + stringToPhone);

    String[] x = stringToPhone.split("");       

    int i = 0;
    out.print("PHONE NUMBER: " + carrierNum + "-");

    for(i = 0; i <= 7; i++){
        if(x[i].equals("A") || x[i].equals("B") || x[i].equals("C") || x[i].equals("a") || x[i].equals("b") || x[i].equals("c")){
            x[i] = "2";
        }
        if(x[i].equals("D") || x[i].equals("E") || x[i].equals("F") || x[i].equals("d") || x[i].equals("e") || x[i].equals("f")){
            x[i] = "3";
        }
        if(x[i].equals("G") || x[i].equals("H") || x[i].equals("I") || x[i].equals("g") || x[i].equals("h") || x[i].equals("i")){
            x[i] = "4";
        }
        if(x[i].equals("J") || x[i].equals("K") || x[i].equals("L") || x[i].equals("j") || x[i].equals("k") || x[i].equals("l")){
            x[i] = "5";
        }
        if(x[i].equals("M") || x[i].equals("N") || x[i].equals("O") || x[i].equals("m") || x[i].equals("n") || x[i].equals("o")){
            x[i] = "6";
        }
        if(x[i].equals("P") || x[i].equals("Q") || x[i].equals("R") || x[i].equals("S") || x[i].equals("p") || x[i].equals("q") || x[i].equals("r") || x[i].equals("s")){
            x[i] = "7";
        }
        if(x[i].equals("T") || x[i].equals("U") || x[i].equals("V") || x[i].equals("t") || x[i].equals("u") || x[i].equals("v")){
            x[i] = "8";
        }
        if(x[i].equals("W") || x[i].equals("X") || x[i].equals("Y") || x[i].equals("Z") || x[i].equals("W") || x[i].equals("x") || x[i].equals("y") || x[i].equals("z")){
            x[i] = "9";
        }
        equiPhoNum = x[i] + "";
        if(equiPhoNum != " " && equiPhoNum != null){
            s1.setAttribute("Value1", equiPhoNum); 
        }
        out.print(s1.getAttribute("Value1"));
    }

Answer 1

I would suggest you create the equipPhoNum string before you check for the condition. As it stands now, for each iteration, it will check

if(equiPhoNum != " " && equiPhoNum != null)

and remember, you are using the default delimiter which is split("") so the first element will be a blank space " ". So the compiler skips

s1.setAttribute("Value1", equiPhoNum);

Then after that, you want to print a value that has not been set. You will surely get a NullPointerException or something similar. So move the condition outside of the for loop and try it once more.

Let us know what the result is.