We are proud to announce the open source release of J2ObjC, a Google-authored translator that converts Java source code into Objective-C source for iPhone/iPad applications.
J2ObjC enables Java code to be part of an iOS application's build, as no editing of the generated files is necessary. The goal is to write an application's non-UI code (such as data access, or application logic) in Java, which can then be shared by Android apps, web apps (using GWT), and iOS.
You can go to the J2ObjC project page for instructions on how to use the tool, check out the source code and view the list of reported issues. The site also has detailed design docs for anyone interested in how the translator works.
By Tom Ball, Google Engineer, Mountain View