How to check validity of access token in java code

I've 2 programs one to get the token and serialize it and the other is to deserialize it and use it maybe on another pc
i want the first one to read the .ser file that generated from the last use and check if it is valid or not
so i have two solutions now
1- make the first program create small file and test the access token to upload it and then delete it if it is uploaded.
2- make the first program get new access token every time and serialize it.
thanks for your reply :)