JTable implements COPY drag-n-drop (DND) data transfer support *at the component level* (1.4) ... so if you want to DND a *cell* within the JTable, you have to get creative...
First place to reference might be the sun tutorial (
http://java.sun.com/docs/books/tutorial/uiswing/misc/dnd.html#transferableClasses)
If you look at the 'data transfer support' chart, you'll probably realize that you'll have to break-out some custom code to get the job done. (For example JTable will treat 'text' cells as JLabels by default, ... and you won't find JLabel on the chart..)
At the minimum, you'll need to write a custom transfer handler. In a broader case, I imagine you could write custom DND component(s) to represent the cell(s) in your table, and/or your table.
[Incidentally, I tried to solve this problem not too long ago, and I backed out because (1) I'm not crazy about the
Java DND support (I find it it a little unresponsive i.e. difficult to trigger drag-selection with the mouse in a table/list), and (2) Cell selection in the JTable is not always first-click ...
Instead, I attached a mouselistener to the JTable, and I use the left-double-click to 'export' value of current cell, and right-double-click to import it to selected cell. Tho this is pretty much equivalent to a cell-level copy-n-paste accelerator key sequence, but a few less clix:-)
hth