It was for a job interview, I wouldn't specify what the challenge is but they said I could use any language I want; I chose Python. They said I failed the coding interview because it was not Java.

Sounds like evey college-course ever.

Had something like that as well.

API calls had to be mocked, so when the application didn't work because there was no actual API behind it they saw it as a bug, even though I did exactly as the task description described.
It was for a frontend position, so of course I'm not going to supply a functional backend.

Were you applying to be a barista or something? ;)

Bullet successfully dodged.

Lucky you! :)

What if you're really the dumb one. I won't hire someone that'll choose python over java for developing an android app (say that was the challenge)