Re: Is RPG 'DEAD"

["Aaron Bartell" <aaronbartell@xxxxxxxxx>]

Just wanted to provide some input on the garbage collection and
OutOfMemoryError stuff you brought up Corr.

I wrote an entire Java application that ran on a Canon copier/scanner/fax
machine (one of those with the big LCD touch screens) and it most definitely
had the potential to run out of memory (to the point where I could make it
happen almost at will).  Here is a section of code for how I trapped memory
errors and *attempted* to free garbage.  You should note that reading Suns
garbage collection documentation is required to really understand what is
going on.  For example, the below System.gc() didn't always free up as much
memory as I expected it to based on the document images I was processing.
Anyways, take it for what it's worth...

                try {
                    if (garbageCollect)
                        System.gc();
                    garbageCollect = !garbageCollect;

                    byte[] newCopy = new byte[oar.data.length];
                    System.arraycopy(oar.data, 0, newCopy, 0,
oar.data.length);
                    outStream.write(newCopy);
                    outStream.flush();

                } catch (IOException e) {
                    Log.out(Log.getStackTrace(e));
                } catch (OutOfMemoryError e) {
                    Log.out("!!!!!!!!!!!!!!!!!!Out Of MEMORY
ERROR!!!!!!!!!!!!!!!!");
                    Log.out(Log.getStackTrace(e));

                    ignoreRemainingImages = true;
                    if (currentJobId > 0)
                        Device.cancelJob(currentJobId);
                    readEnd();
                    UICommand.imageTransferError("ERR002", "Page " +
currentPage
                            + " exceeded maximum image size.");

                    return false;
                }

BTW, programming for hardware is pretty fun, but WAY different than what I
am normally used to, but still quite fun once you figure out the "flow" of
setting up and tearing down communications.

Aaron Bartell
http://mowyourlawn.com

On Thu, Jun 19, 2008 at 1:23 AM, Takken, Cor <cor.takken@xxxxxxxxxx> wrote:

> It has been some time since I ever read such an entertaining (and long)
> thread. I will react only once and then lean back again and enjoy this
> thread.
>
> First of all, I agree with all of you who have suggested that this
> 'consultant' should be asked to either name the IBM-guys and come up
> with documents supporting this bold statement or resign his job (and
> then climb some high mountains just to repent). RPG is not dead (or
> alternatively: as dead as COBOL), and neither is Java or C#. All
> languages have their purpose and right application, RPG is not for
> high-end graphical applications and Java or C# have their strengths in
> other fields.
>
> Now for some other things:
>
> Java is better because it prevents memory-leaks (or words to that
> extent).
> Java as a language is not better. The language Java has no thing as a
> garbage collector, and it does not prevent memory-leaks. The virtual
> machine which processes the Java code (or the intermediate compiled
> bytecode) needs to implements a few interfaces. Implementing interfaces
> means that you need to accept calls to certain functions with certain
> parameters, however nowhere in the documentation of Sun does it say HOW
> you need to implement these calls. I would even put it a bit stronger:
> the Java documentation explicitly states that there is absolutely no
> guarantee that calls to the garbage collection will guarantee anything
> to be cleaned up. Cleaning up after badly written programs is the
> responsibility of the JVM, but if the JVM decides never to clean up...
> well then nothing is cleaned up, and at some point even the JVM will run
> out of memory and there is no try catch finally in the world that will
> catch this because no program will run. Is java then better? I would
> argue that it is not (but I will stand corrected) since there is no code
> that will allow me to explicitly remove objects (it allows me to use
> "new " to create objects, but is there a "old" or "cleanup" function to
> kill created objects?).
>
> Classes are comparable to modules or service programs
> RPG IV is not an object oriented language, Java is. Classes represent
> runnable code which can only be used once instantiated as an object
> (barred static methods), modules and service programs can be compared to
> static (so class-level) methods. Classes are abstract descriptions of
> objects, objects are instantiations of classes and represent a class in
> a certain state which can behave in a predescribed way (the code in the
> class) as is fit for that state. A module is not a class, a module is a
> stream of code which can be called from the outside to perform some
> functionality and that is it. A module is always a single thing, there
> is no way for an application to instantiate the same module in more than
> one instantiation and use them next to each other or simultaneously. The
> whole concept of RPG does not even allow this and while I appreciate
> that there are ways to simulate such behaviour (e.g. copy the same
> module to different locations or by renaming the compiled object) that
> would still be a simulation and not have the same flexibility as object
> instantiation. The whole programming concept of RPG is different from
> Object Oriented (or close to Object Oriented) languages as Java, C++,
> C#, etc. You can't compare the two except on the bare line to line code
> basis (comparing if-statements etc.).
>
> And again: this consultant should either produce the hard evidence of
> the demise of RPG or forever hold his peace.
>
> Kind regards,
>
> Cor