Well, the Java ME branch split off from Desktop Java early (Java SE 1.2), and cell phones are very different platforms, more limited in many ways than desktop computers, but Java ME applications should run on any cell phones that support the Java ME platform.
There are some code-grammar writing differences such as angle bracket type safety that didn't make it into Java ME, like "<
String>," but overall Java platforms aren't so much different languages, the code syntax is mostly the same, but they have different APIs -- the prepackaged Object libraries.
If you're having trouble moving a concept from the Java SE api into Java ME api, please post your question. That is what this area of the coderanch is for.