On the Horizon: an Apache-License Version of Java

mparaz writes "Geir Magnusson of the Apache Software Foundation announced a J2SE 5 implementation project called 'Harmony.' It covers the virtual machine and the class libraries, and aims to pass the Sun specification. A FAQ is available."

Comments

JamVM

[Hugo Graffiti]

I hope they choose JamVM for the VM. It's a fairly new VM but impressively lean and mean (100k executable that still supports the full spec). From the JamVM web site, here is a list of the main features:

• Uses native threading (posix threads). Full thread implementation including Thread.interrupt()
• Object references are direct pointers (i.e. no handles)
• Supports class loaders
• Efficient thin locks for fast locking in uncontended cases (the majority of locking) without using spin-locking
• Two word object header to minimise heap overhead (lock word and class pointer)
• Execution engine supports basic switched interpreter and threaded interpreter, to minimise dispatch overhead (requires gcc value labels)
• Stop-the-world mark and sweep garbage collector
• Thread suspension uses signals to reduce suspend latency and improve performance (no suspension checks during normal execution)
• Full object finalisation support within the garbage collector (with finaliser thread)
• Garbage collector can run synchronously or asynchronously within its own thread
• String constants within class files are stored in hash table to minimise class data overhead (string constants shared between all classes)
• Supports JNI and dynamic loading for use with standard libraries
• Uses its own lightweight native interface for internal native methods without overhead of JNI
• JamVM is written in C, with a small amount of platform dependent assembler, and is easily portable to other architectures.

Re:Better for the Linux User

[DrXym]

The same could be said for Kaffe, gcj, classpath et al. And in fact it probably has been, each in their time being heralded as a way to break from Sun.

Sadly the reality is that no Java is even remotely as reliable or complete as Sun's implementation for the desktop let alone anywhere else. Major work had to be done to gcj just to make Open Office 2.0 run, which hardly speaks for its maturity. And other impls such as Kaffe are missing critical security functionality such as byte code verification. And enterprise level functionality? Forget it.

Personally I'd love to see a free and open source Java, but its taken years to get this far and its still not there yet.

Harmony could use Parrot

[mattr]

I'm just someone not involved in language development, and so I'm sorry if I'm out of line. Most developers in language X just sit back in admiration at the olypmian efforts of language, compiler, vm or kernel designers. But I would like to humbly suggest that Harmony people talk with the parrot people. Parrot already has a java bytecode converter proof of concept, initial code, will run on tons of platforms, and has perl and python people too. It is GPL compatible and licensable under the Perl Artistic License.

The reason I suggest this is that it would appear that the main purpose of the Harmony project is to create a vibrant, inclusive community. In that case, the open source world, Harmony, and Parrot, plus users of java, perl, python, ruby and tcl (for starters) can all benefit by combining two disparate groups of all-star programmers working in potentially complementary areas.

If any parts of the Harmony project can use parts being developed for Parrot, much time would be saved and the quality of both projects could increase. In addition, it would likely be easier for the Harmony project to meet its stated goals of collaboration and sharing of runtime components, etc. to do so with parrot. The Parrot FAQ also talks a bit about VM development, including working with a JVM, it sure sounds like there is some overlap with Harmony.

Perhaps the Parrot people don't need any help (I doubt they would say so though) and maybe the Harmony VM people can't stand the idea of not building from ground zero, or using only the Apache license and nothing else. If any of these three maybes are true then it is a sad story.

Also, I may be out of line but it sounds like parrot will enable sharing of code from different languages at runtime. If so that will just magnify what Harmony is trying to do in terms of bringing people together.

So humbly I would like to say that the ideas of creating a specification and reference implementation, and promoting collaboration and sharing of modular code sounds wonderful, and focusing on these and not wasting time reinventing the wheel could be a great move for Harmony, and contribute to refocusing the brainpower of the free software world, in the spirit of the Harmony and Parrot projects.

My guess is that Harmony has some really smart people and they are also well aware of the Parrot effort. Maybe some are already involved for all I know. Any comments one way or the other?