Thanks for reply Rob.
But this TableModel.getColumnClass(int column) did not solve my problem. I have created a JTable using Object[cells][columnNames] and so all the cells are Object data type. I would like to set column class instead of get column class.
I do not quite understand this sentence:
The easiest way is to subclass DefaultTableModel and override getColumnClass.
I do not know how to subclass something. I was thinking about overriding it, but I do not know how and I am not sure it will help.
The other my idea is to create a JTable using Vector type, but i do not know if there will be more options to set column data type and also I am afraid it will cost me much more time to convert my table to Vector type.
Martin