Had the same issue and wasted hours before realizing that “unable to change permissions for owner: C:\Users\Quibbles.credentials\drive-api-quickstart”
is just a warning.
The real issue is the null pointer here.
InputStream in =
DriveQuickstart.class.getResourceAsStream("/client_secret.json");
This line was the issue in my case. “in” was null and hence the null pointer.
InputStream in = new FileInputStream("<Full Path>\\client_secret.json");
This resolved my issue.