Retrieving a ArrayList from Session variables

Question

I am trying to retrieve information from an ArrayList that I set in the session variables. But it isn't being set correctly some where because I get a null pointer when I run searchList.isEmpty()
The servlet part:

case "searchProducts":
    ArrayList<Product> searchList = new ArrayList<>();//create array
    Product testProduct = new Product(1500,"test","testing",100); //create product
    searchList.add(testProduct); //add product to ArrayList
    session.setAttribute("searchList", searchList);//sets session value to ArrayList
    view = request.getRequestDispatcher("SearchProduct.jsp"); //set view to JSP
    break;

The JSP where I'm trying to get the info looks like this, I'm including the different things I've tried. The JSP:

<%
                ProductService ps = new ProductService();
                ArrayList<Product> searchList = (ArrayList<Product>)session.getAttribute("searchProduct");
                out.println(searchList.isEmpty());
                    //end test items


//                    if(searchList.isEmpty()== false){
//                        for(int count = 0; count < searchList.size(); count++){
//                            out.println("<option>");
//                            out.println(searchList.get(count).getName());
//                            out.println("</option>");
//                        }//end for
//                    }//end if
%>

Any help is greatly appreciated!

seems you are not calling correct attibute. You are filling 'searchList' but after, you are calling 'searchProduct' — OscarBcn
– OscarBcn, Commented May 8, 2016 at 17:16
You set as session.setAttribute("searchList", searchList); therefore you should use ArrayList<Product> searchList = (ArrayList<Product>)session.getAttribute("searchList"); — rickz
– rickz, Commented May 8, 2016 at 17:20

Programmer1994 · Accepted Answer · 2016-05-08 17:17:31Z

1

Typo in your code. You used "searchList" as key when you set the attribute but when you try to retreive it , you use session.getAttribute("searchProduct"); searchProduct isn't set/doesn't exist and so,

session.getAttribute("searchProduct");

returns null and gives a nullpointerexception upon calling isEmpty().

answered May 8, 2016 at 17:17

Programmer1994

9853 gold badges13 silver badges30 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Kevin Over a year ago

Oh my goodness. I've been looking at this thing forever. Thank you Cedric absolutely fixed the problem :)

Collectives™ on Stack Overflow

Retrieving a ArrayList from Session variables

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related