Resizing JTable Cells

Answer:
To the best of my knowledge, it is not possible to do this with JTable. At least there's no easy way of doing it, but it may be possible with some serious acrobatics.

One possible starting point may be to fake the effect by creating a custom CellRenderer that paints a cell over some of its adjacent cells. The difficulty in customizing JTable to do what you're asking is that JTable doesn't store individual component cells, but instead aggregates them into a set of TableColumnModels that take care of drawing the cells.

You may wish to make use of GridBagLayout and represent each cell as an AWT component if you have a relatively small amount of data to display. GridBagLayout will allow you to place components so that they consume varying amounts of rows or columns in a grid.