access Google spreadsheet using java core application without UI -

i using oauth 2.0 , google apis authorize user download spreadsheet saved in google drive, programmatically. although in appproach authorization code needs extracted url, opens web page asks user's google account sign in. how do without having login ui, application in middle layer , and can things programmatically. missing on here? possible download and/or access spreadsheet using google api without needing ui sign in?

yes possible. make spreadsheet public. official docs show how read public spreadsheet.
other options dont require public spreadsheet make own service acts middle layer spreadsheet. if dont have lot of users can free apps script content service. user ajax apps script piblished url spreadsheet data can further cache apps script cache service.