Q:

Upload files to Google Drive from App Engine application

I'm trying to implement App Engine app that should upload files from user computer to Team Drive folder. 
Currently I'm trying to do it with .jsp and servlets but it seems that it couldn't be done that way.
I'm using Service Account and Drive API Client Library for Java - https://developers.google.com/api-client-library/java/apis/drive/v3
It seems that when uploading files in such way you should use java.io.File which is impossible on App Engine, because file isn't stored on instance but it is uploaded from user computer.
Is it any way to upload file directly to Google Drive using App Engine?
Additional note:
I'm using Drive API v3.
In Drive API v2 there was file.insert() method available which lets you sending InputStream as input parameter. I think such method could help me with upload but it is not included in API v3.
https://developers.google.com/drive/api/v2/reference/files/insert

A:

I think you're looking for protected Create(File content, com.google.api.client.http.AbstractInputStreamContent mediaContent) from https://developers.google.com/resources/api-libraries/documentation/drive/v3/java/latest/

