Java SE (Java Platform, Standard Edition)

Hey, I'm a postgrad student working on a software project and I need to get an existing java program to work on a pocket pc as part of a greater system. I've never used a pda of any description before and don't have much experience with java so I'm not sure exactly what's required. I presume I'll have to install a JRE of some description but if anyone has any experience or words of wisdom I'd really appreciate it,
cheers.