Error while populating drop down list with values from a database

Question

Hi all,
I have a JSP page with a drop down list that is to be populated with values from a database.
This is the code in my JSP file:
     <!-- Form for picking the floor -->
         <!-- Get the available floors -->
         <% ArrayList<Integer> floornumbers = dataManager.getAllFloorNumbers();
            Iterator<Integer> iterator = floornumbers.iterator(); %>
         <!-- Create the form for users to select the floor -->
         <form id="floorselectionform">
              <input type="hidden" name="action" value="floorselected"/> <!-- Guides the servlet to redirect to the appropriate page -->
              Select floor | <select name="floorselector" id="floorselector">
                   <% while (iterator.hasNext()) { %>
                   <option value="<%=iterator.next().intValue()%>"> <%=iterator.next().intValue()%> </option>
                   <% } %>
              </select>
              <input type="submit" value="Go!"/>
         </form>   The DataManager.java class simply forwards this to its respective Peer class, which has the code shown below:
      package seatplanner.model;
    import java.sql.Connection;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.sql.Statement;
    import java.util.ArrayList;
    /* This class handles all floor operations */
     public class FloorPeer
     /* This method returns all the floor numbers */
     public static ArrayList<Integer> getAllFloorNumbers(DataManager dataManager) {
        ArrayList<Integer> floornumbers = new ArrayList<Integer>();
        Connection connection = dataManager.getConnection();
        if (connection != null) {
          try {
            Statement s = connection.createStatement();
            String sql = "select ID from floor order by ID asc";
            try {
              ResultSet rs = s.executeQuery(sql);
              try {
                while (rs.next()) {
                  floornumbers.add(rs.getInt(1));
              finally { rs.close(); }
            finally {s.close(); }
          catch (SQLException e) {
            System.out.println("Could not get floor numbers: " + e.getMessage());
          finally {
            dataManager.putConnection(connection);
        return floornumbers;
     }  The classes compile properly, but when I load this page up in Tomcat it just freezes and does not load the form. I tested the DB connection and it works fine.
What am I doing wrong in the JSP code?
Thanks for the help in advance.
UPDATE: I commented out the form, and added <%=floornumbers.size()%> right above the commented code to check if the ArrayList is indeed getting populated with the values from the database (the values are of type integer in the database). The page still freezes like before. I'm puzzled now :confused: .

Answer 1

Wrong usage of Iterator.
<!-- Form for picking the floor -->
         <!-- Get the available floors -->
         <% ArrayList<Integer> floornumbers = dataManager.getAllFloorNumbers();
            Iterator<Integer> iterator = floornumbers.iterator(); %>
         <!-- Create the form for users to select the floor -->
         <form id="floorselectionform">
              <input type="hidden" name="action" value="floorselected"/> <!-- Guides the servlet to redirect to the appropriate page -->
              Select floor | <select name="floorselector" id="floorselector">
                   <% while (iterator.hasNext()) {
                                Integer inte = iterator.next();
                        %>
                   <option value="<%=inte.intValue()%>"><%=inte.intValue()%></option>
                   <% } %>
              </select>
              <input type="submit" value="Go!"/>
         </form>or make use of enhanced loop as you are already using J2SE 5.0+ for avoiding confusions.
<!-- Form for picking the floor -->
         <!-- Get the available floors -->
         <% ArrayList<Integer> floornumbers = dataManager.getAllFloorNumbers(); %>
         <!-- Create the form for users to select the floor -->
         <form id="floorselectionform">
              <input type="hidden" name="action" value="floorselected"/> <!-- Guides the servlet to redirect to the appropriate page -->
              Select floor | <select name="floorselector" id="floorselector">
                   <% for(Integer inte:floornumbers) {%>
                   <option value="<%=inte.intValue()%>"><%=inte.intValue()%></option>
                   <%}%>
              </select>
              <input type="submit" value="Go!"/>
         </form>and a lot better thing would be making usage of basic Taglib provided with JSTL spec or struts spec which make life easier and simple.
something like usage of <c:forEach/> or <logic:iterate/> would be lot better without writing a single scriptlet code.
Hope that might help :)
REGARDS,
RaHuL