the code ain't working

My problem is that i want each selected combobox appear in jtable when the person press on add button

My code here only choose one, once i choose another book from combobox it remove the old in jtable and add the new.

How should i fix it?

try t jDuttonl.addActionListener (new java.awt. event. Actionlistener () ( public void actionRerformed(java.awt.event.Actionkvent evt) (