javaexceptionawt-eventqueue

Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: -1 error


So I'm having trouble with an application I've been working on and I only saw one other post with the -1 error and doesn't seem to help me with what is going on. We have an items tab that when you click on a consignor, it should display the items and it does, but it spits out this error and sometimes doesn't update.

Error:

   Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: -1
at com.GiggaFriggs.ItemPanel$5.valueChanged(ItemPanel.java:502)
at javax.swing.JList.fireSelectionValueChanged(Unknown Source)
at javax.swing.JList$ListSelectionHandler.valueChanged(Unknown Source)
at javax.swing.DefaultListSelectionModel.fireValueChanged(Unknown Source)
at javax.swing.DefaultListSelectionModel.fireValueChanged(Unknown Source)
at javax.swing.DefaultListSelectionModel.fireValueChanged(Unknown Source)
at javax.swing.DefaultListSelectionModel.changeSelection(Unknown Source)
at javax.swing.DefaultListSelectionModel.changeSelection(Unknown Source)
at javax.swing.DefaultListSelectionModel.removeSelectionIntervalImpl(Unknown Source)
at javax.swing.DefaultListSelectionModel.clearSelection(Unknown Source)
at javax.swing.JList.clearSelection(Unknown Source)
at javax.swing.JList.setModel(Unknown Source)
at javax.swing.JList.setListData(Unknown Source)
at com.GiggaFriggs.ItemPanel.refreshItemList(ItemPanel.java:533)
at com.GiggaFriggs.ItemPanel$4.valueChanged(ItemPanel.java:460)
at javax.swing.JList.fireSelectionValueChanged(Unknown Source)
at javax.swing.JList$ListSelectionHandler.valueChanged(Unknown Source)
at javax.swing.DefaultListSelectionModel.fireValueChanged(Unknown Source)
at javax.swing.DefaultListSelectionModel.fireValueChanged(Unknown Source)
at javax.swing.DefaultListSelectionModel.fireValueChanged(Unknown Source)
at javax.swing.DefaultListSelectionModel.changeSelection(Unknown Source)
at javax.swing.DefaultListSelectionModel.changeSelection(Unknown Source)
at javax.swing.DefaultListSelectionModel.setSelectionInterval(Unknown Source)
at javax.swing.JList.setSelectionInterval(Unknown Source)
at javax.swing.plaf.basic.BasicListUI$Handler.adjustSelection(Unknown Source)
at javax.swing.plaf.basic.BasicListUI$Handler.mousePressed(Unknown Source)
at java.awt.AWTEventMulticaster.mousePressed(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

Code:

package com.GiggaFriggs;


import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import java.text.NumberFormat;
import java.text.SimpleDateFormat;
import java.util.Date;

import javax.swing.BorderFactory;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFormattedTextField;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.ListSelectionModel;
import javax.swing.border.TitledBorder;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;

public class ItemPanel extends JPanel {


    protected static int conID;

    private int itemID;
    private JLabel itemIdLabel;
    private JTextField searchTF;
    private JRadioButton conRB, dealRB;
    private ButtonGroup searchBG;
    private JButton searchB;
    protected static JList <String> conList;
    private static JList <String> itemList;
    private JScrollPane itemPane;
    private String[] sampleItemA;
    private JFormattedTextField priceTF;
    private JTextField itemDesTF;
    private JFormattedTextField lowPriceTF;
    private JComboBox<?> categoryCB;
    final private String[] categoryListA = { "Home Decor", "Womens Accessories", "Furniture", "Collectables"};
    private JTextField commentsTF;
    private static final String IMG_PATH = "src/images/testImage.jpg";

    protected static String[] conSampleList;
    private JLabel priceL;
    private JLabel lowPriceL;
    private JButton saveB;
    private JButton newB;
    private JButton deleteB;
    private JButton sellB;
    protected static Consigner[] consignerList;
    private JScrollPane scrollPane;
    private static int conMarker;

    static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";  
    static final String DB_URL = "jdbc:mysql://173.194.80.143:3306/Test";
    static Connection conn = null;
    static Statement stmt = null;
    private final SimpleDateFormat sdf = new SimpleDateFormat("MM/dd/yy");

    public ItemPanel(){

        conMarker = 0;
        consignerList = DatabaseConnector.pullConInfoDB();
        conSampleList = new String[consignerList.length];

        for (int i = 0; i < conSampleList.length; i++){
        conSampleList[i] = "ID " + String.valueOf(consignerList[i].getIdNumber() + "     " + consignerList[i].getLastName() + ", " + consignerList[i].getFirstName());
        }
        //consignerID = consignerList[0].getIdNumber();

        searchTF = new JTextField("Search for Consigner/Dealer");
        searchB = new JButton("Search");
        conList = new JList<String>(conSampleList);
        conList.setVisibleRowCount(5);
        conList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        conList.setSelectedIndex(0);
        scrollPane = new JScrollPane(conList);
        sampleItemA = new String[consignerList[conMarker].items.length];

        for (int i = 0; i < sampleItemA.length; i++){
            if(consignerList[conMarker].items[i].isSold() == false)
            sampleItemA[i] = consignerList[conMarker].items[i].getItemDesc();
        }

        itemList = new JList<String>(sampleItemA);
        itemList.setVisibleRowCount(5);
        itemList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        itemList.setSelectedIndex(0);
        itemPane = new JScrollPane(itemList);
        itemIdLabel = new JLabel("Item # " + Integer.toString(itemID));
        itemDesTF = new JTextField(consignerList[conMarker].items[0].getItemDesc());
        itemDesTF.setColumns(21);
        categoryCB= new JComboBox<String>(categoryListA);
        categoryCB.setSelectedItem(consignerList[conMarker].items[0].getCategory());
        priceTF = new JFormattedTextField(NumberFormat.getNumberInstance());
        priceTF.setColumns(5);
        priceTF.setValue(consignerList[conMarker].items[0].getSalePrice());
        lowPriceTF = new JFormattedTextField(NumberFormat.getNumberInstance());
        lowPriceTF.setValue(consignerList[conMarker].items[0].getLowBid());
        lowPriceTF.setColumns(5);
        priceL = new JLabel("Requested Price");
        lowPriceL = new JLabel("Lowest Price Accepted");
        commentsTF = new JTextField(consignerList[conMarker].items[0].getComments());
        conRB = new JRadioButton("Consigner", true);
        dealRB = new JRadioButton("Dealer", false);
        searchBG = new ButtonGroup();
        searchBG.add(conRB);
        searchBG.add(dealRB);
        saveB = new JButton("Save/Edit");
        newB = new JButton("New Item");
        deleteB = new JButton("Delete Item");
        sellB = new JButton("Sell Item");
        saveB.setDefaultCapable(true);
        saveB.getPreferredSize();


    }

    public static int getConMarker() {
        return conMarker;
    }


    protected JPanel createItemsPanel(){

        JPanel outerPanel = new JPanel();
        outerPanel.setLayout(new GridBagLayout());
        GridBagConstraints c = new GridBagConstraints();
        //adding constraints to items and adding them to the panel
        c.fill = GridBagConstraints.BOTH;
        c.gridx = 0;
        c.gridy = 0;
        c.gridwidth = 2;
        outerPanel.add(searchTF, c);

        c.gridx = 2;
        outerPanel.add(searchB, c);

        c.gridwidth = 1;
        c.gridx = 0;
        c.gridy = 1;
        outerPanel.add(conRB, c);

        c.gridx =1;
        outerPanel.add(dealRB, c);

        c.gridy =2;
        c.gridx = 0;
        c.gridwidth = 2;
        outerPanel.add(scrollPane, c);

        JPanel innerPanel = new JPanel();
        innerPanel.setLayout(new GridBagLayout());
        GridBagConstraints c2 = new GridBagConstraints();
        c2.fill = GridBagConstraints.BOTH;
        TitledBorder titled = BorderFactory.createTitledBorder("Item Information");
        innerPanel.setBorder(titled);

        c2.gridx = 0;
        c2.gridy = 0;
        c2.insets = new Insets(10,10,10,10);
        innerPanel.add(itemIdLabel, c2);


        c2.gridx = 1;
        c2.gridwidth = 2;

        innerPanel.add(itemPane, c2);


        //this is how you show an image
//      try{
//          BufferedImage img = ImageIO.read(new File(IMG_PATH));
//          ImageIcon icon = new ImageIcon(img);
//          pictureLabel = new JLabel(icon);
//          
//      } catch (IOException e){
//          e.printStackTrace();
//      }

//      c2.gridx = 4;
//      c2.gridwidth = 1;
//      innerPanel.add(pictureLabel, c2);

        c2.gridx = 0;
        c2.gridy=1;
        c2.gridwidth = 2;
        innerPanel.add(itemDesTF, c2);

        c2.gridx = 2;
        c2.gridwidth = 1;
        innerPanel.add(categoryCB, c2);

        c2.gridx = 0;
        c2.gridy = 2;
        innerPanel.add(priceL, c2);

        c2.gridx = 2;
        c2.gridwidth = 1;
        innerPanel.add(priceTF, c2);

        c2.gridx = 0;
        c2.gridy = 3;
        innerPanel.add(lowPriceL, c2);

        c2.gridwidth = 1;
        c2.gridx = 2;
        innerPanel.add(lowPriceTF, c2);

        c2.gridwidth = 3;
        c2.gridx = 0;
        c2.gridy =4;
        innerPanel.add(commentsTF, c2);

        c2.gridwidth = 1;
        c2.gridx = 0;
        c2.gridy = 5;
        innerPanel.add(saveB, c2);

        c2.gridx = 1;
        innerPanel.add(deleteB, c2);

        c2.gridx = 2;
        innerPanel.add(newB, c2);

        c2.gridx = 3;
        innerPanel.add(sellB, c2);

        c.gridy = 3;
        c.gridx = 0;
        c.gridwidth = 5;
        outerPanel.add(innerPanel, c);

        EditHandler eh = new EditHandler();
        saveB.addActionListener(eh);
        SearchingHands sh = new SearchingHands();
        searchB.addActionListener(sh);
        searchTF.addActionListener(sh);

        newB.addActionListener(
                new ActionListener(){

                    @Override
                    public void actionPerformed(ActionEvent arg0) {
                        // TODO Auto-generated method stub
                        conMarker = (int) conList.getSelectedIndex();
                        consignerList = DatabaseConnector.pullConInfoDB();
                        System.out.println(conMarker);
                        System.out.println(consignerList[conMarker].itemsForSale());

                        if (consignerList[conMarker].itemsForSale() < 15 ){
                        NewItem ni = new NewItem();
                        ni.setUpInter();
                        } else {
                            JOptionPane.showMessageDialog(null,
                                    "Sorry",
                                    "This Consignor already has 15 items for sale",
                                    JOptionPane.ERROR_MESSAGE);
                        }

                    }

                });

        deleteB.addActionListener(
                new ActionListener(){

                    @Override
                    public void actionPerformed(ActionEvent e) {
                        int x = (int) itemList.getSelectedIndex();
                        String temp = itemIdLabel.getText();
                        String temp2 = temp.substring(7);
                        int i = Integer.parseInt(temp2);
                        System.out.println(i);

                        String input = (String)JOptionPane.showInputDialog(
                                null,
                                "Why are you deleting this item?",
                                "Deleting " + consignerList[conMarker].items[x].getItemDesc(),
                                JOptionPane.PLAIN_MESSAGE,
                                null, null, "Explain Yourself!!!");


                        try{
                            Class.forName("com.mysql.jdbc.Driver");

                            conn = DriverManager.getConnection(DB_URL, "root", "swingset");
                            stmt=conn.createStatement();

                            String sq1 = "UPDATE items SET itemStatus = 'D', itemComments = '" + input + "' WHERE itemID = " + i;

                            stmt.executeUpdate(sq1);

                            conn.close();

                        } catch (SQLException ex){
                            ex.printStackTrace();
                        }catch(Exception er){
                            er.printStackTrace();
                        }


                        consignerList[conMarker].items[x].setSold(true);

                        refreshConList();
                        refreshItemList(conMarker);


//                      
//                      Object[] options = {"Yes",
//                      "No"};
//                      int n = JOptionPane.showOptionDialog(null,
//                          "Are you sure you want to delete this item?",
//                          "Delete Item?",
//                          JOptionPane.YES_NO_OPTION,
//                          JOptionPane.QUESTION_MESSAGE,
//                          null,     //do not use a custom Icon
//                          options,  //the titles of buttons
//                          options[0]); //default button title
//                      
//                      if (n == JOptionPane.YES_OPTION){
//                      
//                          try{
//                              Class.forName("com.mysql.jdbc.Driver");
//                              
//                              conn = DriverManager.getConnection(DB_URL, "root", "swingset");
//                              stmt=conn.createStatement();
//                              
//                              String sq1 = "DELETE FROM items WHERE itemID = " + i;
//                              stmt.executeUpdate(sq1);
//                              
//                              conn.close();
//                              
//                          } catch (SQLException ex){
//                              ex.printStackTrace();
//                          }catch(Exception er){
//                              er.printStackTrace();
//                          }


                        }

                    }

                );
        sellB.addActionListener(

                new ActionListener(){

                    @Override
                    public void actionPerformed(ActionEvent e) {
                        int x = (int) itemList.getSelectedIndex();
                        double soldFor = 0.00;
                        String input = (String)JOptionPane.showInputDialog(
                                            null,
                                            "How much are you selling " 
                                                    + consignerList[conMarker].items[x].getItemDesc() + " for?",
                                            "Selling " + consignerList[conMarker].items[x].getItemDesc(),
                                            JOptionPane.PLAIN_MESSAGE,
                                            null, null, "$00.00");

//                      String input = JOptionPane.showInputDialog("Selling " + consignerList[conMarker].items[x].getItemDesc(), "How much are you selling " 
//                              + consignerList[conMarker].items[x].getItemDesc() + "for?");

                        try{
                        soldFor = Double.parseDouble(input);

                        } catch (NumberFormatException ex){
                            JOptionPane.showMessageDialog(null,
                                    "Please Enter a Number.",
                                    "That is not a Number!!!!",
                                    JOptionPane.ERROR_MESSAGE);
                        }

                        if (soldFor >= consignerList[conMarker].items[x].getLowBid()){ 

                            consignerList[conMarker].items[x].sellItem(soldFor);

                            String temp = itemIdLabel.getText();
                            String temp2 = temp.substring(7);
                            int i = Integer.parseInt(temp2);
                            Date d = new Date();
                            String soldDate = sdf.format(d);
                            //SimpleDateFormat sdf = new SimpleDateFormat("EEE, MMM dd, yyy");
                            //Calendar calendar = new GregorianCalendar();
                            //calendar.add(Calendar.DAY_OF_MONTH, 90);
                            //consignerList[conMarker].items[x].setCreatedOn(sdf.format(calendar.getTime()));

                            try{
                                Class.forName("com.mysql.jdbc.Driver");

                                conn = DriverManager.getConnection(DB_URL, "*****", "*******");
                                stmt=conn.createStatement();

                                String sq1 = "UPDATE items SET itemSoldFor = '" + soldFor + "' WHERE itemID =  '" + i + "AND itemStatus = 'S' WHERE itemID = " + i + "ANDitemSoldDate = '" + soldDate + "' WHERE itemID = " + i;
//                              String sq2 = "UPDATE items SET itemStatus = 'S' WHERE itemID = " + i;
//                              String sq3 = "UPDATE items SET itemSoldDate = '" + soldDate + "' WHERE itemID = " + i;

                                stmt.executeUpdate(sq1);
//                              stmt.executeUpdate(sq2);
//                              stmt.executeUpdate(sq3);

                                conn.close();

                            } catch (SQLException ex){
                                ex.printStackTrace();
                            }catch(Exception er){
                                er.printStackTrace();
                            }


                            refreshItemList(conMarker);
                        } else {
                            JOptionPane.showMessageDialog(null,
                                    "The Consignor wants more money than that man.",
                                    "Not Enough Moola",
                                    JOptionPane.ERROR_MESSAGE);
                        }


                    }});//end of sellB action Listener

        conList.addListSelectionListener(

        new ListSelectionListener(){

            @Override
            public void valueChanged(ListSelectionEvent e){

                int conMarker = (int) (conList.getSelectedIndex());


                refreshItemList(conMarker);

//              System.out.println(conMarker);
//              System.out.println(consignerList[conMarker].items.length);
//              if (consignerList[conMarker].hasItems() == true) {
//                  
//              String[] testA;
//              
//              testA = new String[consignerList[conMarker].items.length];
//              
//              for (int i = 0; i < testA.length; i++){
//                  if(consignerList[conMarker].items[i].isSold() == false)
//                  testA[i] = consignerList[conMarker].items[i].getItemDesc();
//              }
//              
//              itemList.setListData(testA);
//              //itemPane.setViewportView(itemList);
//              } else {
//              //  itemList.setVisible(false);
//              String[] noItems = new String[1];
//              noItems[0] = "No Items for Sale";
//              itemList.setListData(noItems);
//              }

            }

        }


        );//end of conList Listener


        itemList.addListSelectionListener(

        new ListSelectionListener(){

            @Override
            public void valueChanged(ListSelectionEvent e){

                int conMarker = (int) (conList.getSelectedIndex());
                int i = (int) itemList.getSelectedIndex();

                itemID = consignerList[conMarker].items[i].getItemNumber();
                itemIdLabel.setText("Item # " + Integer.toString(itemID));
                itemDesTF.setText(consignerList[conMarker].items[i].getItemDesc());
                categoryCB.setSelectedIndex(consignerList[conMarker].items[i].getCategory());
                priceTF.setText(Double.toString(consignerList[conMarker].items[i].getSalePrice()));
                lowPriceTF.setText(Double.toString(consignerList[conMarker].items[i].getLowBid()));
                commentsTF.setText(consignerList[conMarker].items[conMarker].getComments());        
            }
        });//end of itemList Listener


        outerPanel.setVisible(true);

        return outerPanel;
    }

    public static void refreshItemList(int conMarker){


        if (consignerList[conMarker].hasItems() == true) {

            String[] testA;

            testA = new String[consignerList[conMarker].items.length];

            for (int i = 0; i < testA.length; i++){
                if(consignerList[conMarker].items[i].isSold() == false)
                testA[i] = consignerList[conMarker].items[i].getItemDesc();
            }

            itemList.setListData(testA);
            //itemPane.setViewportView(itemList);
            } else {
            //  itemList.setVisible(false);
            String[] noItems = new String[1];
            noItems[0] = "No Items for Sale";
            itemList.setListData(noItems);
            }

    }

    public static void refreshConList(){
        consignerList = DatabaseConnector.pullConInfoDB();

        conSampleList = new String[consignerList.length];

        for (int i = 0; i < conSampleList.length; i++){
        conSampleList[i] = "ID " + String.valueOf(consignerList[i].getIdNumber() + "     " + consignerList[i].getLastName() + ", " + consignerList[i].getFirstName());
        }   

        //conList.setListData(conSampleList);
    }

    private class EditHandler implements ActionListener{

        @Override
        public void actionPerformed(ActionEvent e){

            String temp = itemIdLabel.getText();
            String temp2 = temp.substring(7);
            int i = Integer.parseInt(temp2);
            conMarker = (int) (conList.getSelectedIndex());




            try{
                Class.forName("com.mysql.jdbc.Driver");

                conn = DriverManager.getConnection(DB_URL, "*****", "*******");
                stmt=conn.createStatement();


                String sq1 = "UPDATE items SET itemDesc = '" + itemDesTF.getText() + "' WHERE itemID = " + i + "AND itemSalePrice = " + Double.parseDouble(priceTF.getText()) + " WHERE itemID = " + i + "AND itemLowBid = " + Double.parseDouble(lowPriceTF.getText()) + " WHERE itemID = " + i + "AND itemComments = '" + commentsTF.getText() + "' WHERE itemID = " + i + "AND itemCategory = '" +categoryCB.getSelectedIndex() + "' WHERE itemID = " + i;
//              String sq2 = "UPDATE items SET itemSalePrice = " + Double.parseDouble(priceTF.getText()) + " WHERE itemID = " + i;
//              String sq3 = "UPDATE items SET itemLowBid = " + Double.parseDouble(lowPriceTF.getText()) + " WHERE itemID = " + i;
//              String sq4 = "UPDATE items SET itemComments = '" + commentsTF.getText() + "' WHERE itemID = " + i;
//              String sq5 = "UPDATE items SET itemCategory = '" +categoryCB.getSelectedIndex() + "' WHERE itemID = " + i;

                stmt.executeUpdate(sq1);
//              stmt.executeUpdate(sq2);
//              stmt.executeUpdate(sq3);
//              stmt.executeUpdate(sq4);
//              stmt.executeUpdate(sq5);
                conn.close();

            } catch (SQLException ex){
                ex.printStackTrace();
            }catch(Exception er){
                er.printStackTrace();
            }

            refreshConList();
            refreshItemList(conMarker);


        }
    }

    private class SearchingHands implements ActionListener{

        @Override
        public void actionPerformed(ActionEvent event){

            int x = 0;

            try{
                x = Integer.parseInt(searchTF.getText());
            } catch (NumberFormatException e){
                JOptionPane.showMessageDialog(null,
                        "Please Enter a Number.",
                        "That is not a Number!!!!",
                        JOptionPane.ERROR_MESSAGE);
            }



            if (x >= 0 && x <= consignerList.length){

                conMarker = x;
                conList.setSelectedIndex(x);
                String[] testA = new String[consignerList[conMarker].items.length];

                for (int i = 0; i < sampleItemA.length; i++){
                    if(consignerList[conMarker].items[i].isSold() == false)
                    testA[i] = consignerList[conMarker].items[i].getItemDesc();
                }

                itemList.setListData(testA);
                itemList.setSelectedIndex(0);

            } else {

                JOptionPane.showMessageDialog(null,
                        "Please Enter a Number between 0 & " + (consignerList.length) + ".",
                        "Not In Range!",
                        JOptionPane.ERROR_MESSAGE); 
            }

        }

    }




}

Solution

  • getSelectedIndex will return a value of -1 if no value is selected in the JList conList. Ensure both JList components have selected items before attempting to access any fields in the list consignerList

    if (!conList.isSelectionEmpty() && !itemList.isSelectionEmpty()) {
     ...
    }