What would be required to make a truely portable app?
I'm talking about it being able to go across platforms, rather Linux, Windows, or Mac.
I know it has to be 100% self reliant, or to pull from the resources that is common in all.
Java requires the Java libraries to be installed, which is true for almost all languages. You could probably try for something like java script to increase the likely hood the libraries are already there, but this is still not guaranteed.
Seems like a discussion that would be fun to explore, and it's a good place.