adding rows to coloumns. Netbeans

Dear sir,

I am making simple GUI application in Netbeans6.5.

I want to add row through code during run time of program.

I have one jtable and one jbutton on the frame .

If i press jbutton then there should be addition of one row in the jtable for this i have added the following code in jbutton action performed function

Jtable.addRowSelectionInterval(0,jtable.getRowCoun t()-1);

But i am not able to achieve the task . the number of rows same as that were in the beginning i.e. number of rows are not increasing on pressing the jbutton

Also i have refreshed the jframe for that but still it doesn't work

Please tell me the solution for that.

regards
gaurav