need a little help with dialog/message boxes

[arj1982]

I'm pretty new to writing programs in java and i have a school assignment. First, i need to know how to change the text in the title bar of an input dialog box, a message dialog box and a confirm dialog box. Also, the way i have it set up is that in the first input box, i need to be able to know if the user hits 'cancel' and send the program to a different part. right now, if the user hits cancel, the whole program goes away and i get error messages that say 'number format exception: null' i'm so confused someone please help!
i've attached the panel i created...maybe that will clear up what it is i'm trying to do.