java - Google Drive service account domain-wide delegation not working offline -

i have service account domain-wide delegation

i building credentials following code:

googlecredential.builder()                 .settransport(new nethttptransport())                 .setjsonfactory(new jacksonfactory())                 .setserviceaccountid(appconfig.service_account_id)                 .setserviceaccountprivatekeyfromp12file(privatekey)                 .setserviceaccountscopes(collections.singleton(drivescopes.drive_metadata_readonly))                 .setserviceaccountuser(user.getemail())                 .build(); 

and getting drive service that:

drive.builder(             new nethttptransport(),             jacksonfactory.getdefaultinstance(), credential)             .setapplicationname("drive-demo")             .build(); 

everything works smoothly when have opened gdrive in browser. browser tab not connected app anyhow. when browser closed , session expired - can't fetch drive. credential token gets updated , i'm not getting error or exception.

is there kind of 'access-type = offline' domain-wide account? did miss?

looking @ domain-wide delegation docs in drive, doesn't mention works offline.