How to change device hostname

[calvinpaivaa]

I want to change the hostname of the device. I know currently it takes the device codename. But i would like to change that.
My device is Samsung A3 (2015) SM-A300F (a3lte). Currently my hostname show as a3lte. I want to change that. I tried changing it in /etc/hostname and /etc/hosts, but after after the app restarts, it goes back to a3lte. Please let me know how to permanently change. I also tried changing the device name in build prop too. That didn't work. Please let me know. Thanks.