LangLanguage Obj-CObjective C
License Apache 2
ReleasedLast Release Mar 2015

Maintained by Larry Tin, Massimo Dragano.


  • By
  • Google Inc.

J2ObjC: Java to Objective-C Translator and Runtime

Project site: http://j2objc.org
J2ObjC blog: http://j2objc.blogspot.com
Questions and discussion: http://groups.google.com/group/j2objc-discuss

What J2ObjC Is

J2ObjC is an open-source command-line tool from Google that translates Java code to Objective-C for the iOS (iPhone/iPad) platform. This tool 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 app's non-UI code (such as data access, or application logic) in Java, which is then shared by web apps (using GWT), Android apps, and iOS apps.

J2ObjC supports most Java language and runtime features required by client-side application developers, including exceptions, inner and anonymous classes, generic types, threads and reflection. JUnit test translation and execution is also supported.

J2ObjC is currently between alpha and beta quality. Several Google projects rely on it, but when new projects first start working with it, they usually find new bugs to be fixed.

What J2ObjC isn't

J2ObjC does not provide any sort of platform-independent UI toolkit, nor are there any plans to do so in the future. We believe that iOS UI code needs to be written in Objective-C or Objective-C++ using Apple's iOS SDK (Android UIs using Android's API, web app UIs using GWT, etc.).


  • JDK 1.7 or higher
  • Xcode 5 or higher
  • Mac OS X 10.9 or higher


This library is distributed under the Apache 2.0 license found in the LICENSE file.