dbTable.getTable().unregisterKeyboardAction(KeyStroke.getKeyStroke(KeyEvent.VK_F3,0));

JTable table = dbTable.getTable();

table.getInputMap(JTable.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT).put(KeyStroke.­getKeyStroke("TAB"), "disableTab"); 

//the code below may not be needed

//add this code only if the above line creates any exception

table.getActionMap().put("disableTab", new AbstractAction() 

{ 

 public void actionPerformed(ActionEvent e) 

 { 

 //don't do any thing

 }

}