Nullpointerexception when inserting in mysql database

Question

I am trying to insert a data from one of my jinternal frame to mysql database. I am using a resultset class method for the insert. I always end up having the NullPointerException even though the variables is not null. I can't pinpoint to where I am having this null exception in my code. Here is the snippet of actionListener for my jbutton:

public void actionPerformed(ActionEvent e) {
    String action = e.getActionCommand();
    String fabric = txtFabric.getText();
    String supplier = txtSupplier.getText();

    if(action.equals("Add")){
        btnAdd.setText("Save");
        btnAdd.setActionCommand("Save");
        txtFabric.setEnabled(true);
        txtFabric.grabFocus();
        txtSupplier.setEnabled(true);
        txtFabric.setText("");
        txtSupplier.setText("");
    }
    else if(action.contentEquals("Save")){
        if(fabric.isEmpty() || supplier.isEmpty()){
            System.out.println("Nothing to save");
        }
        else{
            System.out.println(fabric+" "+supplier);
            try {
                model.addFabric(fabric, supplier); // the error points to this line
            } catch (SQLException e1) {
                e1.printStackTrace();
            }
        }

        btnAdd.setText("Add");
        btnAdd.setActionCommand("Add");
        txtFabric.setEnabled(false);
        txtSupplier.setEnabled(false);
        tableModel.fireTableDataChanged();
    }
}

And here is the snippet of my class method insert:

public void addFabric(String item,String supplier) throws SQLException
{
    try{
        sql = "INSERT INTO fabric(ItemDesc,Supplier) values(?,?)";
        pstmt = con.prepareStatement(sql);
        pstmt.setString(1, item);
        pstmt.setString(2, supplier);
        pstmt.executeUpdate();
    }
    catch(Exception ex){
        ex.printStackTrace();
    }finally{
        pstmt.close();
        con.close();
    }
}

and here is the exception that I am getting pointing to the line of insertion:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at main.Fabric.actionPerformed(Fabric.java:148)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(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$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.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)

where did you create model object? And fabric, supplier shouldn't be null. — Pirate, Oct 12 '16 at 07:55
`model` seems to be an instance variable, are you sure it is initialized? — Daniel Szalay, Oct 12 '16 at 07:57
should I initialize it? I only declare it private static ModelDB model. — SilverRay, Oct 12 '16 at 08:04
The fabric and the supplier is not null because I am printing them before inserting to database, check my code you'll see it. — SilverRay, Oct 12 '16 at 08:05
I initialize it as model = null but it still creates the exception. — SilverRay, Oct 12 '16 at 08:25
@SilverRay You should not initialize it to null, you should create the object by using constructor or you should call a method which returns `model` object. Something like this `ModelDB model = new ModelDB();` — Ravikumar, Oct 12 '16 at 08:34
Thanks it's now saving and the exception is gone. My only problem now is to refresh the jtable after the save. — SilverRay, Oct 12 '16 at 08:38

Nullpointerexception when inserting in mysql database

0 Answers0