It translates Java to Objective-C code without GC support (uses reference counting which you need to annotate). It doesn't define any UI so effectively you need to work on a Mac just without all the wonderful tools for UI building that apple provides and without any of the WORA you get from Java. When something doesn't work you are still stuck debugging in Objective-C. And googling stack overflow trying to understand how to translate Objective-C code to your problem.
Codename One solves all of the above issues by giving "actual WORA" which is the true value of Java.
Codename One solves all of the above issues by giving "actual WORA" which is the true value of Java.