Comments on: Core Java on iPhone

By: Jay Freeman (saurik)

Jay Freeman (saurik) — Sat, 22 Dec 2007 03:07:12 +0000

Oh, just to be more clear: you can write “native” iPhone applications in Java/JavaScript, as in, that work exactly like built-in applications and operate on the same library. This is due to my JocStrap library, that connects Java to Objective-C.

If anyone needs more support than what JocStrap currently provides (which is a number of frameworks including WebKit, Celestial, and UIKit), I’d be happy to either activate it or fix it. ;P

By: Jay Freeman (saurik)

Jay Freeman (saurik) — Sat, 22 Dec 2007 02:59:30 +0000

The answer to when you can run Java applications on your iPhone is immediately, and for the last week or two ;P.

If you add the repository http://apptapp.saurik.com/ to Installer.app and install a bunch of stuff you will be able to write _graphical_ applications for your iPhone in either Java or JavaScript (thanks to Rhino, and some extra work I put in to JocStrap).

There are also a couple example applications in there: HelloJava and HelloScript. Both include their source code so you can see how they work.

If anyone needs help, send me an e-mail; my contact info is on my website. I also hang out on #iphone on irc.saurik.com, if anyone wants to come and ask questions.

There will probably be a separate website soon for my JocStrap project, and some tutorials of how to write applications now that development isn’t so hectic ;P.

By: David Herron

David Herron — Tue, 18 Dec 2007 17:47:57 +0000

Yes, Robert, I agree the situation as it stands is not ideal.

By: Robert Lougher

Robert Lougher — Tue, 18 Dec 2007 17:16:33 +0000

I should also add that in the absence of the JCK, the open-source community has been working on Mauve. This is a collaborative effort to write a free test suite for the Java™ class libraries :

http://sources.redhat.com/mauve/

JamVM and GNU Classpath are regularly ran against Mauve. The results can be found on comp.java.classpath.testresults :

http://news.gmane.org/gmane.comp.java.classpath.testresults

Or directly from GNU Classpath’s official autobuilder and regression tester:

http://builder.classpath.org/

By: Robert Lougher

Robert Lougher — Tue, 18 Dec 2007 16:47:58 +0000

Regarding compatibility. It is using JamVM 1.5.0 with GNU Classpath 0.96.1.

JamVM 1.5.0 implements the publically available Java Virtual Machine Specification Second Edition, and the JNI specification, including additions up to JDK 1.5.

GNU Classpath 0.96.1 aims for 100% compatibility with JDK 1.5 but it isn’t complete. Its API compatibility is tested by Japitools, and the results are publically available:

Against JDK 1.4 (92.63%) :

http://www.kaffe.org/~stuart/japi/htmlout/h-jdk14-classpath.html

Against JDK 1.5 (88.33%) :

http://www.kaffe.org/~stuart/japi/htmlout/h-jdk15-classpath.html

However, neither JamVM or GNU Classpath has been tested against, let alone passed, the Java Compatibility Kit (JCK). This is required for certification and to be “Java Compatible”.

Having said that, Sun have not made the JCK available to open-source projects so it’s hardly surprising that they haven’t been tested against it.

With the release of OpenJDK, Sun have announced a new license for the JCK (OpenJDK Community TCK license):

http://www.infoq.com/news/2007/08/openjdk-jck

However, to qualify for access to the compatibility tests the project must be “substantially derived” from the OpenJDK itself. This means the JamVM/GNU Classpath combination would still not be able to be tested as both are clean-room implementations and are in no way derived from OpenJDK.

By: Vinod Ponmanadiyil

Vinod Ponmanadiyil — Tue, 18 Dec 2007 11:53:44 +0000

Please note that this is not J2ME. So your old games etc still wont work.

By: Techblissonline Dot Com

Techblissonline Dot Com — Tue, 18 Dec 2007 10:25:54 +0000

so when will we java apps on iphone?

By: David Herron

David Herron — Mon, 17 Dec 2007 22:56:47 +0000

Thank you for your correction. Perhaps my vision on this is blinded a little by working inside the Java SE team. To us the word ‘Compatible’ when said like ‘Java Compatible’ means that it has passed the testing which allows for certification.. namely, the Java TCK (JCK). Doing some adhoc testing like “it runs a few commands” is like saying “this code ‘works’ for some definition of ‘works’”. I own an iPod Touch and would love to have Java on the thing. But in my role as a Java SE team member I’m very interested in knowing that when something claims to be ‘Java’ that it really is ‘Java’.

By: Vinod Ponmanadiyil

Vinod Ponmanadiyil — Mon, 17 Dec 2007 21:52:51 +0000

The port apparently IS capable of running JSE 1.5 command line applications.

By: Vinod Ponmanadiyil

Vinod Ponmanadiyil — Mon, 17 Dec 2007 21:42:55 +0000

Thanks David. I have made the corrections. Jay’s project page though states about 1.5 core classes. I need to verify the version compatibility more further.