J2ObjCiOS App Access to Java Libraries Tom Ball, Google Senior Software Engineer http://j2objc.googlecode.com but it won't work . why on earth?" . with Android/iOS doing catch-up ● Java-based client-server service layer ○ Only shared by GWT and Android clients ○ Protocol changes needed fast turnaround ● Crazy idea: write translator ○ "Okay..." ."Google.First day tweet ● Frustration developing multi-platform application ● GWT app leading development. com) ○ Syntax translation only.google. output won't build ○ Project in early dev. abandoned .Projects Evaluated ● FlexyCore/in-the-box ○ iOS port of Dalvik VM and Android APIs ○ Rejected: non-standard L&F. iOS license conflicts ● XMLVM ○ Many translation bugs ○ Significant pieces of JRE missing ○ Java -> ObjC translation no longer supported ● java2objc (code.. builds and links with iOS app ● Run within Xcode or on command-line ○ Debug with Xcode or GDB . ● Converts Java source code to Objective C ○ Foundation Framework focus ○ No editing needed ● Has an open-source JRE (subset) runtime ● Translates.J2ObjC J2ObjC is a new source translator/compiler. linked into app ● Debug using Xcode or GDB J2ObjC is not for one-time source translation ● Comments removed.What J2ObjC Isn't J2ObjC is not a cross-platform application tool ● No cross-platform UI support J2ObjC is not a Java emulator ● Objective C code is generated ● Compiled to object files. output reformatted . ..What is Supported? ● ● ● ● ● ● ● ● ● ● ● ● Full Java 6 syntax (Java 7 coming) Inner and anonymous classes Exceptions.. try/catch/finally Static variables Enums Autoboxing Synchronization Fields use Objective C properties JSNI-style native code embedding Java collections JUnit test translation . concurrent java. Android source ● Similar subset as GWT ○ ○ ○ ○ java. java. java.logging.math.reflect java.lang.nio (subset) ● Apache Harmony tests used for verification .JRE ● Based on Apache Harmony.util. java.util.io (subset) java. java.lang.util. release.Three Memory Options ● Resource Counting (default) ○ retain. and autorelease calls added ○ dealloc method generated ○ Autorelease pool added to main method ● Automatic Resource Counting (ARC) ○ Full runtime support requires iOS 5 ● Garbage Collection ○ finalize method mapped or generated ○ Not supported on iOS . More Information Project site: http://j2objc.com ○ ○ ○ ○ Downloads Documentation wiki Full source code Issues Email: [email protected] Thanks for listening! .