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Subject: Re: JGNAT and JRE
Newsgroups: comp.lang.ada
References: <1114727090.629742.263970@l41g2000cwc.googlegroups.com>
From: "Ed Falis" <falis@verizon.net>
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Date: Thu, 28 Apr 2005 23:35:47 GMT
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Date: 2005-04-28T23:35:47+00:00
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Fabio,

On Thu, 28 Apr 2005 18:24:50 -0400, fabio de francesco <fmdf@tiscali.it>  
wrote:

> JGNAT seemed working fine with some simple programs until I compiled a
> new one that uses tasks without errors. But when I tried to execute it
> I got "Exception in thread "main"
> java.lang.IllegalMonitorStateException". What is this exception?

JGNAT never made it past compatibility with JDK 1.3, due to lack of  
commercial interest.

> Above all, what really matters is whether or not I can write (1) JGNAT
> is reliable for production use, (2) if it is actively maintained and
> updated, (3) if there exist any kind of practical restrictions in using
> it. Any answers and comments on either these issues or everything
> related would be very appreciated and useful in writing a good Ada
> introduction (I imagine it may matter many of you).

We (AdaCore) dropped active support for this product a few years ago  
because there was no significant commercial interest in Ada running on a  
JVM (and we did give it a fair amount of time and marketing effort).  You  
could also look into AppletMagic from SoftTool or Aonix as an alternative.

JGNAT largely works fine with JDK 1.3 or less.  With 1.4, Sun added some  
additional byte code validation that causes the exception you're seeing.

Unfortunately, what interest we saw in JGNAT was largely confined to  
jokers who thought it would be a way for them to migrate their Ada code  
base to Java. :-P

On the other hand, it is free software, and open to maintenance by others.

- Ed