Missä vika???

Haluan lisätä jTableen tooltipin, joka näyttää taulukon toisen sarakkeen arvon (Stringiä), kun hiiri on sarakkeen päällä, Koodasin seuraavasti:

private void jTableMouseMoved(java.awt.event.MouseEvent evt) {
int mouseOnrow = jTable.rowAtPoint(jTable.getMousePosition());
int mouseOncolumn=jTable.columnAtPoint(jTable.getMousePosition());

if (mouseOncolumn==1) {

jTable.setToolTipText(jTable.getValueAt(mouseOnrow,1).toString());
}
}

Homma toimii kuten haluan, mutta silti saan errorin

Exception in thread "AWT-EventQueue-0" java.lang.IndexOutOfBoundsException: Invalid index
at javax.swing.DefaultRowSorter.convertRowIndexToModel(DefaultRowSorter.java:497)
at javax.swing.JTable.convertRowIndexToModel(JTable.java:2620)
at javax.swing.JTable.getValueAt(JTable.java:2695)
at gui.PatientTablePanel.jTableMouseMoved(PatientTablePanel.java:115)
at gui.PatientTablePanel.access$100(PatientTablePanel.java:43)
at gui.PatientTablePanel$1.mouseMoved(PatientTablePanel.java:101)
at java.awt.AWTEventMulticaster.mouseMoved(AWTEventMulticaster.java:313)
at java.awt.AWTEventMulticaster.mouseMoved(AWTEventMulticaster.java:312)
at java.awt.Component.processMouseMotionEvent(Component.java:6308)
at javax.swing.JComponent.processMouseMotionEvent(JComponent.java:3273)
at java.awt.Component.processEvent(Component.java:6032)
at java.awt.Container.processEvent(Container.java:2041)
at java.awt.Component.dispatchEventImpl(Component.java:4630)
at java.awt.Container.dispatchEventImpl(Container.java:2099)
at java.awt.Component.dispatchEvent(Component.java:4460)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4574)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4251)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4168)
at java.awt.Container.dispatchEventImpl(Container.java:2085)
at java.awt.Window.dispatchEventImpl(Window.java:2475)
at java.awt.Component.dispatchEvent(Component.java:4460)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
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)


Tosin, en ole sisäistänyt vielä Pointtien käyttöä, aloittelija kun ollaan. Miten errorin saa pois?