Exception with JTable When Edit Cell with Event Listener

Why when i'm editing my JTable by double clicking on a cell, when i'm finish editing and i'm press enter, it success doing the method that i made. but when i'm editing on it and then click on other cell without enter, it will throw new exception like this :

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException   at javax.swing.plaf.basic.BasicTableUI$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)

Here's my code for adding the event listener to my JTable

DefaultTableModel propertiesModel = new DefaultTableModel(tableContent, tableColumn){
            public boolean isCellEditable(int rows, int col) {
                return col == 1;
            };
        };

propertiesModel.addTableModelListener(new TableModelListener() {

            @Override
            public void tableChanged(TableModelEvent e) {
                editProperties();
            }
        });

tableContent and tableColumn is vector for filling the JTable, and editProperties() is method that i made for saving the value edited by user.

Anyone know why this is happen? any answer would be appreciated, thanks!