Question

I am reading following data –

Year, No, Name, 
2009, 1, ABC
2009, 2, PQR
2009, 3, XYZ
2010, 1, BCD
2010, 2, DEF
2010, 3, JKL
2011, 1, FGH
2011, 2, IJK
2011, 3, LMN

Its a sample, there are thousands of these type.
I need to display the unique Year value in JList and for the selected Year, I have to give a CheckBox, which if selected, would display the Name sorted on No, otherwise sorted on Name.

Answer 1

What you need looks like a Map, key will be the Year, and value will be a list of No and Number (you need to create your own class).

Then you need to create two Comparator, one is based on Name, the other is No. So when checkbox is checked, you use Name-based comparator to sort the list, when unchecked, use No-based comparator to sort the list.