I already contacted Ubooquity's dev on this subject, but thought I'd share so someone can give me their input.
So I had this old rooted smartphone lying around and thought I'd make something out of it by making it a small private home server running Ubooquity for me to access and read around the house.
I installed Termux and Termux-Java, and dowloaded the jar file. I ran it, and it says "ERROR on loading inner JAR: Cannot create temp directory /tmp/JarClassLoader". This happens because the /tmp folder on Android is read only, no matter your privileges - unless you wipe it and recreate it with rw permissions, which I'm avoiding. In Termux, there's a variable TMPDIR which defaults to "/data/data/com-termux/files/usr/tmp". Would Ubooquity be open source and I'd changed this myself but since it is not, if no one can see a solution to this problem, I propose the following solutions:
1. If exists, use the path specified on TMPDIR environment variable, otherwise, maintain current behavior
2. Allow to specify through an argument where to create the temp files
I'm sure both these solutions would be useful in other case scenarios and not just my specific problem.
Thank you all for your time and if anyone has a workaround to this problem, I'm all ears!
Customer support service by UserEcho