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"Team Ada: Ada Advocacy Issues (83 & 95)" <[log in to unmask]>
Tucker Taft <[log in to unmask]>
Thu, 16 Jul 1998 18:54:09 -0400
Tucker Taft <[log in to unmask]>
text/plain (56 lines)
> I am putting together some notes for the author of a Java book who writes
> as if he has never heard of Ada, or even of CORBA or DCE.  I'm just hoping
> to get Ada mentioned where he discusses alternatives to Java for
> distributed computing (he currently mentions Javascript, VBscript, TCL/Tk,
> and ActiveX).  I would appreciate if someone who knows will answer one or
> more of the following questions:
> 1. Since Ada does not force you to handle an exception, what will happens
>    if I download an applet created by ObjectAda, if it raises an exception
>    that is not handled?

The same thing that happens in Java if you don't handle an exception.
It propagates up to the task, the task dies.  It calls the
"unhandledException" method of the task group just before it dies.

Note that Java has a set of exceptions which need not be mentioned
in the "throws" clause, and which can easily be unhandled.
Any throwable class derived from Error or RunTimeException need not be
mentioned in the throws clause, even if it is explicitly "throw"n.

The reasoning behind this is that some exceptions are thrown implicitly
by the Java VM, and it would not be practical for all such exceptions
to be listed in the "throws" clause.

>    AppletMagic?
>    the GNAT-to-Jcode that's coming soon?

I suspect these both work the same way.  We use classes
derived from "RunTimeException" to represent Ada exceptions,
so they don't need to be mentioned in the throws clause.

> 2. Any other vendor have an Ada-to-Jcode compiler out or expected within a
>    year?  (if so, question  1  applies)
> 3. I've heard rumors of a Smalltalk-to-Jcode compiler.  Anyone know more
>    than a rumor of this or any other language?

There is a web-site which keeps track of such things:

Take a look there.  It mentions a Smalltalk-to-Java source compiler,
among many other things.

> I don't even care in this case if they make Java look a lot better.  I
> just hope to let some folks know that Java is not the only game in town.
> He was honest enough to recommend ActiveX or one of those script languages
> as better than Java for certain circumstances, so maybe he'll treat Ada
> and Eiffel with an open mind.
> Thanks,
>    Wes Groleau