I have a MIDP2.0 mobile device with no support for a specific JSR (it's JSR 180 SIP API for J2ME). Sun's website says there's a reference implementation but it seems it's already removed.
The question is, can I develop JSR 180 and deploy it to the device, so applications can use it? Or should it be in the device firmware (obviously I don't have easy access to it)?
Thank you for answers, links, guides, any information I can get (for a noob trying to remember Java ME).
JSRs are part of the device's Java ME platform and therefore you (as an application developer) cannot modify them (including adding new classes).
However, there is nothing stopping you from reimplementing some (or all) of the features of a JSR in your own application, working around the problem. However, you would not be able to duplicate the correct package names to make your code 'fully' compliant with the actual JSR.
I have not looked at JSR 180 myself, so I don't know how much extra work this would be, but I have in past done something similar with JSR 172 (XML/Web Services) where I wrote my own basic XML parser and web services wrapper.