Can you convert the object returned by jTable.getValueAt(Row,Col) to an integer?

Yes, as long as it is an integer, or it can be parsed to one.

that is.,
say, ob is an Object,
int i = Integer.parseInt((String)ob);

that is.,
say, ob is an Object,
int i = Integer.parseInt((String)ob);

Only if ob can be cast to a String. Of course you created the JTable and know better what you put in there. Since you know what you put to each cell, cast it to the appropriate class, and act accordingly