I wrote some info in the feature request (https://sourceforge.net/p/jstock/feature-requests/167) but i t's quite old and could not be noticed, so i will repaste it here:
I would like to implement integration of jstock with Warsaw Stock Exchange (in polish named GPW). It would be a part of my M.Sc. diploma, so there are high chances that this will happen and will be made correctly :). However there is small issue with the data - the free data sources which are currently available for GPW provides us with data which is 15 minutes delayed (where by delay i mean that data is available instantly, but it's 15 minutes old). Would it make sense to implement it in such case? I know it's not as great as real time data, but my question is more about if this somehow breaks jstock work logic, etc.
No. No logic will be break as JStock is not designed as real time stock market software. Btw, may I know where do you get data from? Is it reliable enough? Do they provide history data feed?
You can get all history data from BOS bank website:
It's updated daily and very reliable