如何在Android上将TM-2度坐标转换为lat lon？

I am writing a program that convert TM-2 degree to lat/lon on Android, but I can't find formula for that. I do find some example on internet, but most of them are convert with open source library, that I can't use on Android platform. I also find a java class that do convert from UTM to lat lon, but it seems no suitable for TM 2 degreen coordinate system. So my question is: how do I convert TM 2 degree coordinate to lat/lon? Where can I find formula?I am writing a program that convert TM-2 degree