Question

I have a rather confusing setup for a program that lets the user choose the number of rows in a table in a jDialog, input data, and returns the data in several arrays (for each column) to the main form. I thought things were going pretty smoothly up to last night, but this morning the table keeps giving me a NullPointerException error no matter what I do. I’ve done some research online and tested the table several times, and I don’t know what’s wrong.
Here’s what I have: (Also, the data from the first column is ignored, it’s not a mistake. My table has 7 columns.)

This is where the exception is being thrown; I’m trying to access the data of column 7.

public int[] getWDurabilityEV() {
    int rowCount = tbl_Units.getRowCount();
    int[] value = new int[rowCount];
    for (int i=0;i<value.length;i++) {
        value[i] = Integer.parseInt(tbl_Units.getValueAt(i, 6).toString());
    }
    return value;
}

This is the button click event on the main form (the other gets are exactly like my example with a different column index; the for loop at the end is an example of how I’m updating the table on my main form)

   private void EVButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                          
        dialog_EV1 EV1 = new dialog_EV1(new javax.swing.JFrame(), true);
//setting values
        EV1.ev1_weapon = ev1_weapon;
        EV1.ev1_wstrength = ev1_wstrength;
        EV1.ev1_wrange = ev1_wrange;
        EV1.ev1_wrate = ev1_wrate;
        EV1.ev1_wdurability = ev1_wdurability;
        EV1.ev1_wportability = ev1_wportability;
        EV1.setData();
        EV1.show();
//getting values
        ev1_weapon = EV1.getWeapon();
        ev1_wstrength = EV1.getWStrengthEV();
        ev1_wrange = EV1.getWRangeEV();
        ev1_wrate = EV1.getWRateEV();
        ev1_wdurability = EV1.getWDurabilityEV();
        ev2_wportability = EV1.getWPortabilityEV();
//calcuating values and updating table
        for (int i=0;i<ev1_weapon.length;i++) {
            tbl_Units.setValueAt(ev1_weapon[i],i,1);
        }   
    } 

And finally, the exception thrown:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at light.dialog_EV1.getWDurabilityEV(dialog_EV1.java:200)
    at light.MainGUI.EVButton1ActionPerformed(MainGUI.java:1061)
    at light.MainGUI.access$100(MainGUI.java:28)
    at light.MainGUI$2.actionPerformed(MainGUI.java:167)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
    at java.awt.Component.processMouseEvent(Component.java:6288)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
    at java.awt.Component.processEvent(Component.java:6053)
    at java.awt.Container.processEvent(Container.java:2041)
    at java.awt.Component.dispatchEventImpl(Component.java:4651)
    at java.awt.Container.dispatchEventImpl(Container.java:2099)
    at java.awt.Component.dispatchEvent(Component.java:4481)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4577)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4238)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4168)
    at java.awt.Container.dispatchEventImpl(Container.java:2085)
    at java.awt.Window.dispatchEventImpl(Window.java:2478)
    at java.awt.Component.dispatchEvent(Component.java:4481)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:643)
    at java.awt.EventQueue.access$000(EventQueue.java:84)
    at java.awt.EventQueue$1.run(EventQueue.java:602)
    at java.awt.EventQueue$1.run(EventQueue.java:600)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:98)
    at java.awt.EventQueue$2.run(EventQueue.java:616)
    at java.awt.EventQueue$2.run(EventQueue.java:614)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:613)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

Answer 1

nothing much to clear from your question, nor from code, please edit your question with SSCCE

1) create public AbstractTableModel for storing data,

2) add TableModel to the JTable

3) add ListSelectionMode (SINGLE_SELECTION) to the JTable,
notice test

if(selectedRow > -1)

4) JTable knows follows data types, then there no reason for parsing Integer from String e.i.