How can I access files of a website running in google console and created using J2EE?

I got a website created in J2EE and running from google developer console compute engine. I searched for buckets, there is no. I tried to connect FTP but failed. I can establish SSH connection though but I don't know where the files are stored. I just got a ubuntu command console. Can anybody help me to find out how can I get my files and how to edit them?