Ask HN: What is a good phone for to write code on?

How about a Windows tablet?

None. Even tablets are considerably less than optimal (believe me, I've been trying for years now). Nothing on iOS has been suitable (caveat: I have not tried in the last six months), Android offerings tend to be better.

Java is even worse than some of the other options because of the syntactic noise: too many special characters are required in too many places.

At best you could do some limited code generation if you used some GUI-oriented block mechanism (e.g., Blockly that outputs Java code), but phone displays are small even for that limited form of interaction.

If you can make Coda fit into your workflow, that plus a Bluetooth keyboard can be nice. Other than that, the on screen keyboard will be awful. Find a phone with a real keyboard (which seriously limits your options).

another thing came to mind today

the samsung galaxy note 8 plugged into the hp elite x3 lapdock is a great candidate. doing this gives you a larger screen, keyboard, and trackpad.