Help: Problem with JGnat

Help: Problem with JGnat

[Bin Chen]

Hi,

I used jgnat compile the following Ada program to Java bytecode, it was OK,
but when I ran the .class file, it always threw the following exception.
Could you give me any feedback?

Thank you.

Bin Chen


Exception:

Exception in thread "main" java.lang.IllegalMonitorStateException
        at
jgnat.adalib.system$task_primitives$operations.write_lock__2(s-taprop.adb:22
9)
        at
jgnat.adalib.system$task_primitives$operations.lock_all_tasks_list(s-taprop.
adb:771)
        at
jgnat.adalib.system$task_primitives$operations.enter_task(s-taprop.adb:373)
        at
jgnat.adalib.system$task_primitives$operations.initialize(s-taprop.adb:834)
        at jgnat.adalib.system$tasking._elabb(s-taskin.adb:186)
        at ada_main.adainit(b~main.adb:89)
        at main.main(main.adb)

Sources:

--Pack_Factorial.ads
package Pack_Factorial is
  task type Task_Factorial is --Specification
    entry Start( F:in Positive ); --Rendezvous
    entry Finish( Result:out Positive ); --Rendezvous
  end Task_Factorial;
end Pack_Factorial;

--Pack_Factorial.adb
package body Pack_Factorial is
  task body Task_Factorial is --Implementation
    Factorial : Positive;
    Answer : Positive := 1;
  begin
    accept Start( F:in Positive ) do --Factorial
      Factorial := F;
    end Start;
    for I in 2 .. Factorial loop --Calculate
      Answer := Answer * I;
    end loop;
    accept Finish( Result:out Positive ) do --Return answer
      Result := Answer;
    end Finish;
  end Task_Factorial;
end Pack_Factorial;

--main.adb
with Ada.Text_Io, Ada.Integer_Text_Io, Pack_Factorial;
use Ada.Text_Io, Ada.Integer_Text_Io, Pack_Factorial;
procedure main is
 Thread_1 : Task_Factorial;
 Factorial: Positive;
begin
 Thread_1.Start(5); --Start factorial calculation
 Put("Factorial 5 is ");
 Thread_1.Finish( Factorial ); --Obtain result
 Put( Factorial ); New_Line;
end Main;

Re: Help: Problem with JGnat

[Dr. Michael Paus]

Bin Chen wrote:
> Hi,
> 
> I used jgnat compile the following Ada program to Java bytecode, it was OK,
> but when I ran the .class file, it always threw the following exception.
> Could you give me any feedback?

Which version of Java are you using? JGNAT does not work on recent Java
distributions anymore unless there is  a newer version than the one I have.
(1.1p). See also the comment on http://www.gnuada.org/rpms313p.html about
JGNAT.

Michael

Re: Help: Problem with JGnat

[Marc A. Criley]

"Dr. Michael Paus" wrote:
> 
> Bin Chen wrote:
> > Hi,
> >
> > I used jgnat compile the following Ada program to Java bytecode, it was OK,
> > but when I ran the .class file, it always threw the following exception.
> > Could you give me any feedback?
> 
> Which version of Java are you using? JGNAT does not work on recent Java
> distributions anymore unless there is  a newer version than the one I have.
> (1.1p). See also the comment on http://www.gnuada.org/rpms313p.html about
> JGNAT.

Yep, JGNAT 1.1p works (mostly) fine with with JDK 1.2.2, but tasking is
broken when used with JDK 1.3.  And I've not tried it with JDK 1.4, but
based on what I've seen, I think the likelihood of it working very well
is low.

I've heard that the last supported version of JGNAT worked okay with
1.3, but I know of no access to that version.  In addition, ACT has
terminated support for JGNAT  :-(  Business decision on their part, for
which I can't blame them--their intent is to make a profit, after
all--but I really liked the concept and had been heavily using the
public version.  Oh well.

Marc A. Criley

Re: Help: Problem with JGnat

[Bin Chen]

Thank you very much.

Bin


"Marc A. Criley" <mcq95@earthlink.net> wrote in message
news:3D4A7C39.2AF0BA8@earthlink.net...
> "Dr. Michael Paus" wrote:
> >
> > Bin Chen wrote:
> > > Hi,
> > >
> > > I used jgnat compile the following Ada program to Java bytecode, it
was OK,
> > > but when I ran the .class file, it always threw the following
exception.
> > > Could you give me any feedback?
> >
> > Which version of Java are you using? JGNAT does not work on recent Java
> > distributions anymore unless there is  a newer version than the one I
have.
> > (1.1p). See also the comment on http://www.gnuada.org/rpms313p.html
about
> > JGNAT.
>
> Yep, JGNAT 1.1p works (mostly) fine with with JDK 1.2.2, but tasking is
> broken when used with JDK 1.3.  And I've not tried it with JDK 1.4, but
> based on what I've seen, I think the likelihood of it working very well
> is low.
>
> I've heard that the last supported version of JGNAT worked okay with
> 1.3, but I know of no access to that version.  In addition, ACT has
> terminated support for JGNAT  :-(  Business decision on their part, for
> which I can't blame them--their intent is to make a profit, after
> all--but I really liked the concept and had been heavily using the
> public version.  Oh well.
>
> Marc A. Criley

Re: Help: Problem with JGnat

[Robert Dewar]

"Marc A. Criley" <mcq95@earthlink.net> wrote in message news:<3D4A7C39.2AF0BA8@earthlink.net>...

> I've heard that the last supported version of JGNAT worked okay with
> 1.3, but I know of no access to that version.  In addition, ACT has
> terminated support for JGNAT  :-(  Business decision on their part, for
> which I can't blame them--their intent is to make a profit, after
> all--but I really liked the concept and had been heavily using the
> public version.  Oh well.

Not so much an issue of making a profit, as one of not losing lots of 
$$$ on this product. Unfortunately there was very little commercial
interest.

Robert Dewar
Ada Core Technologies

Re: Help: Problem with JGnat

[David Marceau]

What about trying to turn the JIT compiler off? There's a
switch/environment variable for this in the jdk docs.
That's how it could work with jdk 1.3.  You have to turn the jit
compiler off.  In this mode it's as if it was running the jdk 1.2.2
compiler :)
It's also good to do this when debugging just java IMHO.

Bin Chen wrote:
> 
> Thank you very much.
> 
> Bin
> 
> "Marc A. Criley" <mcq95@earthlink.net> wrote in message
> news:3D4A7C39.2AF0BA8@earthlink.net...
> > "Dr. Michael Paus" wrote:
> > >
> > > Bin Chen wrote:
> > > > Hi,
> > > >
> > > > I used jgnat compile the following Ada program to Java bytecode, it
> was OK,
> > > > but when I ran the .class file, it always threw the following
> exception.
> > > > Could you give me any feedback?
> > >
> > > Which version of Java are you using? JGNAT does not work on recent Java
> > > distributions anymore unless there is  a newer version than the one I
> have.
> > > (1.1p). See also the comment on http://www.gnuada.org/rpms313p.html
> about
> > > JGNAT.
> >
> > Yep, JGNAT 1.1p works (mostly) fine with with JDK 1.2.2, but tasking is
> > broken when used with JDK 1.3.  And I've not tried it with JDK 1.4, but
Hmmm. I remember looking at the jgnat sources and IMHO ACT mapped every
ada task to a java Thread class and not the Runnable Class.
In the HPCJ(High Performance Computing with Java) book, the author
mentioned a flaw with Thread class.
The Thread once started and then after finishing the contents of the
run() would pretend to be garbage collected but it's not.  Which means
if you run 300000 Thread.run()'s you're bound to have a memory/resource
leak issue since the Thread objects are really only garbage collected
when the entire main() process is exited.  This HPCJ book suggests using
a Thread pool which are expected to exist throughout the process
lifetime.  As soon as one Thread is terminated, you may assign another
Runnable to it hence saving resources.i.e Thread pool of say 10000
Threads.  Instantiate and Thread.setTaskRunnable(new adaRunnable(XXX));
and then thisthread.start();  In this manner, it could be a bit more
resilient to memory/resource issues :)  Runnable objects are garbage
collected as expected. Thread objects are not.  I wonder if this has
something to do with the jgnat Tasking being broken?

Cheers,
David Marceau

JGNAT status??? (was: Re: Help: Problem with JGnat)

[Britt Snodgrass]

"Marc A. Criley" <mcq95@earthlink.net> wrote in message 

> I've heard that the last supported version of JGNAT worked okay with
> 1.3, but I know of no access to that version.  In addition, ACT has
> terminated support for JGNAT  :-(  Business decision on their part, for
> which I can't blame them--their intent is to make a profit, after
> all--but I really liked the concept and had been heavily using the
> public version.  Oh well.
> 
> Marc A. Criley

I've been curious if A.C.T. plans a (final?) public release of the
current (final?) JGNAT source code.

I'm also curious what the supported customers (how many?) used it for.
I'm sure the projects would make good Ada interest stories even if
they're not necessarily Ada success stories.

Britt

Re: JGNAT status??? (was: Re: Help: Problem with JGnat)

[Dr. Michael Paus]

Britt Snodgrass wrote:
> "Marc A. Criley" <mcq95@earthlink.net> wrote in message 
> 
> 
>>I've heard that the last supported version of JGNAT worked okay with
>>1.3, but I know of no access to that version.  In addition, ACT has
>>terminated support for JGNAT  :-(  Business decision on their part, for
>>which I can't blame them--their intent is to make a profit, after
>>all--but I really liked the concept and had been heavily using the
>>public version.  Oh well.
>>
>>Marc A. Criley
> 
> 
> I've been curious if A.C.T. plans a (final?) public release of the
> current (final?) JGNAT source code.

Yes, a new public version of the current JGNAT sources would be great
if it is true that a version exists which runs on Java 1.3+. I never
saw any commercial chances for this as a product but anyway it is
an interesting tool to play with. Maybe we can convince ACT to consider
this.

Michael

Re: JGNAT status??? (was: Re: Help: Problem with JGnat)

[David Marceau]

"Dr. Michael Paus" wrote:
> 
> Britt Snodgrass wrote:
> > "Marc A. Criley" <mcq95@earthlink.net> wrote in message
> >
> >
> >>I've heard that the last supported version of JGNAT worked okay with
> >>1.3, but I know of no access to that version.  In addition, ACT has
> >>terminated support for JGNAT  :-(  Business decision on their part, for
> >>which I can't blame them--their intent is to make a profit, after
> >>all--but I really liked the concept and had been heavily using the
> >>public version.  Oh well.
> >>
> >>Marc A. Criley
> >
> >
> > I've been curious if A.C.T. plans a (final?) public release of the
> > current (final?) JGNAT source code.
> 
> Yes, a new public version of the current JGNAT sources would be great
> if it is true that a version exists which runs on Java 1.3+. I never
> saw any commercial chances for this as a product but anyway it is
> an interesting tool to play with. Maybe we can convince ACT to consider
> this.
> 
> Michael

It may not be feasible for the moment but yes it is always interesting
to think of targeting ada code to run on any java vm including cell
phone j2me vm's, palm pilot j2me vm's and smart card javacard vm's.  

Here's the gist how jgnat could work with j2me/javacard:
1)jgnat your ada code
2).class files passed to a converter tool to make it into a converted
applet for target device(MIDP profile)
It's actually doing a check that the services called actually exist on
the target device among other things i.e. some devices don't allow you
to call all the java network services unless you've paid extra for it. 
There are emulators that run the actual converted applet
.jar/.cap/whatever file on linux and windows in a gui that looks like
the target device. Note j2me/javacard are both subsets of the java
language using both different sets of jars in their classpath.
3)pass the converted applet to the install tool which installs the
generated/converted applet into the device in question.

The only thing I am wondering is how reliable are the java/j2me/javacard
vm's compared to ada?  
Are there existing studies examining java reliability vs ada
reliability?
Are there any existing phones/PIMs/smartcards built with ada instead of
java/j2me/javacard?

Cheers,
David Marceau

Re: JGNAT status??? (was: Re: Help: Problem with JGnat)

[Robert Dewar]

"Dr. Michael Paus" <paus@ib-paus.com> wrote in message news:<3D4B982D.7010100@ib-paus.com>...
> Yes, a new public version of the current JGNAT sources 
> could be great.

We have no plans for any further work on JGNAT


?> if it is true that a version exists which runs on Java 
> 1.3+.
. 
It is false. There were indeed filed bugs in this area, but
they were never solved.

> Maybe we can convince ACT to consider
> this.

What is "this"? Doing more work on JGNAT? That's not going
to happen. The sources are out there, the first task would
be to update them to be compatible with the GNAT 5 sources
at gnu.org. That might be an interesting project, but it is
not something that Ada Core will be able to help with.

Robert Dewar
Ada Core Technologies

Re: JGNAT status??? (was: Re: Help: Problem with JGnat)

[Dr. Michael Paus]

Robert Dewar wrote:

>>Maybe we can convince ACT to consider
>>this.
> 
> 
> What is "this"? Doing more work on JGNAT? That's not going
> to happen. The sources are out there, the first task would
> be to update them to be compatible with the GNAT 5 sources
> at gnu.org. That might be an interesting project, but it is
> not something that Ada Core will be able to help with.

"This" meant to release the CURRENT sources IFF there already
exists a version which fixes the problems with recent Java
versions. As you stated that such a version does not exist
"this" has become meaningless :-(

Michael

Re: JGNAT status??? (was: Re: Help: Problem with JGnat)

[Robert Dewar]

"Dr. Michael Paus" <paus@ib-paus.com> wrote in message news:<3D4BF8EB.8020908@ib-paus.com>...
> "This" meant to release the CURRENT sources IFF there 
> already exists a version which fixes the problems with 
> recent Java versions. As you stated that such a version 
> does not exist "this" has become meaningless :-(

Right, if someone wants this fixed, they should work on
fixing it, probably not that hard for someone who knows
the Java VM well.

Re: JGNAT status??? (Volunteers?)

[António Vargas]

Hi


  Its a shame that jgnat is dying.

  Are there skilled (not pseudo skilled) voluntears in Java VM 
and/or Gnat/JGnat internals for a sourceforge project based in 
jgnat1.1p.


  This is just a question not a compromise.
  
  Without critical mass nothing can be done.


  
Ant�nio Vargas
Barcelos - Portugal.


=============================================

dewar@gnat.com (Robert Dewar) wrote in message news:<5ee5b646.0208030636.2a4b1240@posting.google.com>...
> "Dr. Michael Paus" <paus@ib-paus.com> wrote in message news:<3D4B982D.7010100@ib-paus.com>...
> > Yes, a new public version of the current JGNAT sources 
> > could be great.
> 
> We have no plans for any further work on JGNAT
> 
> 
> ?> if it is true that a version exists which runs on Java 
> > 1.3+.
> . 
> It is false. There were indeed filed bugs in this area, but
> they were never solved.
> 
> > Maybe we can convince ACT to consider
> > this.
> 
> What is "this"? Doing more work on JGNAT? That's not going
> to happen. The sources are out there, the first task would
> be to update them to be compatible with the GNAT 5 sources
> at gnu.org. That might be an interesting project, but it is
> not something that Ada Core will be able to help with.
> 
> Robert Dewar
> Ada Core Technologies

Re: JGNAT status??? (Volunteers?)

[Robert Dewar]

antoniovargas@oninet.pt (=?ISO-8859-1?Q?Ant=F3nio_Vargas?=) wrote in message news:<d808281d.0208120523.62f9567c@posting.google.com>...

>   This is just a question not a compromise.

It is impossible for me to guess as an english speaker
what you had in mind with this sentence. For sure you
are seriously misusing the word compromise. How about
trying again to make your meaning clear :-)

RE: JGNAT status??? (Volunteers?)

[Robert C. Leif]

From: Bob Leif
To: António Vargas et al.
You might try another approach. Ask how many of us would pay some
reasonable amount, $50 to $100 for a copy of JGNAT. To add to my heresy,
I would suggest a version of JGNAT that worked with Microsoft's
intermediate language. One very useful old motto is, "If you can't beat
them, join them.

Although Java is not much more than brilliant marketing by SUN, the
creation of microprocessors based on P codes or their successor, J
codes, is a very good approach. The use of J code engines on retarded
chips also makes sense.

-----Original Message-----
From: comp.lang.ada-admin@ada.eu.org
[mailto:comp.lang.ada-admin@ada.eu.org] On Behalf Of António Vargas
Sent: Monday, August 12, 2002 6:24 AM
To: comp.lang.ada@ada.eu.org
Subject: Re: JGNAT status??? (Volunteers?)

Hi


  Its a shame that jgnat is dying.

  Are there skilled (not pseudo skilled) voluntears in Java VM 
and/or Gnat/JGnat internals for a sourceforge project based in 
jgnat1.1p.


  This is just a question not a compromise.
  
  Without critical mass nothing can be done.


  
António Vargas
Barcelos - Portugal.


=============================================

dewar@gnat.com (Robert Dewar) wrote in message
news:<5ee5b646.0208030636.2a4b1240@posting.google.com>...
> "Dr. Michael Paus" <paus@ib-paus.com> wrote in message
news:<3D4B982D.7010100@ib-paus.com>...
> > Yes, a new public version of the current JGNAT sources 
> > could be great.
> 
> We have no plans for any further work on JGNAT
> 
> 
> ?> if it is true that a version exists which runs on Java 
> > 1.3+.
> . 
> It is false. There were indeed filed bugs in this area, but
> they were never solved.
> 
> > Maybe we can convince ACT to consider
> > this.
> 
> What is "this"? Doing more work on JGNAT? That's not going
> to happen. The sources are out there, the first task would
> be to update them to be compatible with the GNAT 5 sources
> at gnu.org. That might be an interesting project, but it is
> not something that Ada Core will be able to help with.
> 
> Robert Dewar
> Ada Core Technologies

Re: JGNAT status??? (Volunteers?)

[Robert Dewar]

"Robert C. Leif" <rleif@rleif.com> wrote in message news:<mailman.1029204062.16204.comp.lang.ada@ada.eu.org>...
> From: Bob Leif
> To: Ant?io Vargas et al.
> You might try another approach. Ask how many of us would 
> pay some
> reasonable amount, $50 to $100 for a copy of JGNAT. To 
> add to my heresy,

I don't see any heresy there. If you think that's a viable
economic model, why don't you put your money where your
mouth is and give it a go? :-)

> I would suggest a version of JGNAT that worked with 
> Microsoft's intermediate language. 

That's technically confused. What distinguishes JGNAT from
the regular version of GNAT is code that depends entirely
on the structure and details of the JVM.

A version of GNAT that generated .NET compatible pseudo-code would be
a completely new project (requiring
effort of the order of person years from people who knew
what they were doing). Yes, perhaps you could derive some
useful input, and even possibly *some* copied code from JGNAT, but in
no sense would this be a "version of JGNAT".

A version of GNAT generating code for .NET is certainly
a perfectly reasonable idea. So far however we have seen
zero interest/demand in such a product.

Robert Dewar
Ada Core Technologies