GCJ: Java generics ala Sun JDK1.5

GCJ: Java generics ala Sun JDK1.5

[David Jung]

Hi.  Quick Q:
According to Sun's site on their prototype javac with support for
generics, they were planning to make generics part of the Java language
spec. as of 1.4, but have delayed it until 1.5.
Is anyone working on adding generics to gcj?  If not, is it a priority to
add it, or will you hang back until after 1.5 has been released by Sun?
Thanks,
-David Jung.


Optional reading :) ......

Motivation:
I'm currently re-evaluating my preferred development environment.
I've always been a C++ developer, but about 4(?) years ago I switched to
Java2 as I liked:
* portability
* comprehensive standard library
* garbage collection

However, I've since switched back to C++ in frustration at no generics
in Java, and poor performance.  Now I'm considering switching again.
My options...

Java:
* GCJ solves performance issues and integrates well with C++
* Generics are slated for introduction in v1.5, and are Sun's javac now.
  (but GCJ doesn't yet support them)
* Will have to make do without operator overloading :(
* In my opinion, the proliferation of Java APIs has not been well
  managed and is a mess ( -but as least there are options!)

C# / .NET:
* Includes all the features of Java that I care about, plus more
* Has a bytecode that is more ameanable to translation to register based 
machines
  (hence performance is better)
* Although standardized, is controlled by MS, which I don't trust
* Open source Mono implementstion is still in early development
* Not deployed as widely as Java, but probably will be
  (instead of too many APIs and duplication, almost no 3rd party APIs yet)

Any comments/suggestions ?

---
Computer Science and Mathematics Division
Oak Ridge National Laboratory
Oak Ridge, TN, USA

Re: GCJ: Java generics ala Sun JDK1.5

[Tom Tromey]

>>>>> "David" == David Jung <jungdl@ornl.gov> writes:

David> According to Sun's site on their prototype javac with support for
David> generics, they were planning to make generics part of the Java language
David> spec. as of 1.4, but have delayed it until 1.5.
David> Is anyone working on adding generics to gcj?

As far as I'm aware, nobody is working on this.

David> If not, is it a priority to add it, or will you hang back until
David> after 1.5 has been released by Sun?

Is it definitely going to be in 1.5?  I don't track Sun's cutting edge
too closely.  Last time I read about generics, there was still some
debate as to whether they would ever go in.

If Sun adds them to the language, then, yes, it will be important for
gcj to support them.  We aim to have a compatible environment.
However, the time scale for such work is indeterminate.  Serious gcj
front end hacking time seems scarce.

My understanding is that the Sun generics are a Java-level change,
that don't require any changes at the JVM level.  If that is still the
case, then in the meanwhile you can use Sun's `javac' to compile to
bytecode, and then compile the bytecode with gcj.  This won't give you
as good performance, but it ought to work.


David> C# / .NET:
David> * Has a bytecode that is more ameanable to translation to
David> register based machines (hence performance is better)

We recommend people compile from .java files, not from .class files.
That avoids some of the inefficiency -- though to be fair I think the
problems are more with our compiler than with the design of the JVM
itself.  Still, I'm willing to be convinced.  Do you have a specific
example of how the C# bytecode design is better?

Tom

Re: GCJ: Java generics ala Sun JDK1.5

[Fergus Henderson]

On 23-Jan-2002, David Jung <jungdl@ornl.gov> wrote:
> C# / .NET:
> * Includes all the features of Java that I care about, plus more
> * Has a bytecode that is more ameanable to translation to register based
>   machines (hence performance is better)

Do you have any evidence of that?

I've heard a number of claims along these lines, but I've yet to see
much in the way of convincing evidence for them.

-- 
Fergus Henderson <fjh@cs.mu.oz.au>  |  "I have always known that the pursuit
The University of Melbourne         |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.