Can I replace RAM or processor in new Mac mini?
No RAM or processor replacement in the Mac Mini 2014
An iFixit teardown reveals this. And @Pol posted a link to macminicolo.net were you can read about the soldered RAM.
The processor and the RAM is soldered onto the motherboard. Even in a clean room, a soldering iron and a steady hand, it would be nearly impossible. You are not allowed to do this on your own, your warranty will expire on this one.
You can replace your RAM yourself, Apple has even provided a guide on how to do it on similar hardware (2012 model). Here you can find the guide: &quot;Mac mini: How to remove or install memory&quot;. No problems with your warranty.