Android Multipart File Upload Using Httpurlconnection - 400 Bad Request Error

I am trying to write a generic code to upload files to any server (Multipart POST). I have tried different headers and request types in my code and various stackoverflow solutions,

Solution 1:

I manage to test my code successfully.

It seems the issue was with the free hosting site. I now created a servlet and tested locally on my machine and I uploaded it to AWS and tested via the device. Both ways, I was able to upload my file from Android.