Override the getCellEditor() method of JTable. In the example below a comboBox editor is displayed in rows 0, 1, 2. All other rows use the default editor:
Joined: Oct 05, 2007
You sir are a fine Gentleman, and I wish you many happy days doing whatever it is you love to do. If there is a way to make sure this post comes up when somebody googles "how do i render a JComboBox in just one particular cell of a JTable, and not in every row of that column", then you will make somebody else as happy as I am now.