here is the logic of comparing dates...regarding expiry date issue
Date values stored as long values.
Every long date representation is qty of milliseconds passed from 01 jan 1970 00:00.
To compare two dates just compare two long values.
When your application starts for the first time (when there is no saved expiration date) - calculate and save expiration date in persistent store.
One day length in milliseconds is represented via constant in DateTimeUtilities
class. Or you may calculate it by yourselft.
this hint is provided by rafo
thnx rafo...thnx simon also