I think they are using Java.
I worked in Java long back, I remember it needed more RAM to run Java apps.
I do not know whats the present situation (I do not work in Java ay more) and not sure in which lang these altarnatives are done (and why they are doing), but it s just a guess.
This is from another thread, but I think worth mentioning
kumarmohit said:
I tried it.
It has thi FFx like tab feature so you can open all the three things in one window,there is wordprocessing, spreadsheet and presentation, all in its own tab in single window. That makes it a killer app a
and it looks good too.