No problem. I have never met a Java-based phone before, so I am just going to give random links, in hope that they help:

https://github.com/nokia-developer/lwuit-for-series-40/ For developing applications
http://stackoverflow.com/tags/series-40/hot For asking questions and finding answers
http://developer.nokia.com/community..._for_Series_40
http://developer.nokia.com/community..._on_the_phones
http://folder.mywibes.com/mobile_coads/hack_nokia_s40/ Multi-tasking?

It seems that accessing system files is not easy - but hopefully, it will not be the first thing you need to do: http://nokias40club.webs.com/apps/fo...s/show/3361345
http://xp-twiks.blogspot.com.au/2010...rity-make.html

For official Nokia software (flashing, accessing all the files, back-ups and the like? Internet seemed to say that it works for Series 40 devices): http://www.cpkb.org/wiki/Nokia_Phoenix_Service_Software

Service manuals and schematics (hopefully, you will never need them): http://www.cpkb.org/wiki/Nokia_Asha_...service_manual

I am not sure if there is an active Series 40-dedicated developer community out there; http://nokias40club.webs.com/apps/forums/ definitely seems to be too slow, like dead.

You are welcome here. No phone should remain a dark and closed place... never mind the intention of manufacturer.

Thank you. Best wishes.
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Per aspera ad astra...