RE: Java versus RPG on iSeries

["Richard Dettinger" <cujo@xxxxxxxxxx>]

I'm not intending to (and will not actually) get into a Java vs. RPG type
discussion.  And I might even
be inclined to agree with the majority of Joe's answers.  If your goal is
to show that Java can do exactly
what RPG can do (in particular using green screens as the UI), you maybe
don't want to be migrating
to Java.  Actually, that's far enough outside the world that I live in that
I'm not qualified to even have an
opinion.

But the issue I really have to take is with this comment:

I've written and taught extensively on the topic, and I believe that Java
(and to
a lesser degree OOP programming in general) is best suited to highly
definable problem
sets, such as middleware, and less suited to complex, changing requirements
such as
those found in business applications.

I don't understand these comments at all.
0) What is a business application?  Yeah, I'm serious... I guess I don't
know.
1) What makes middleware a highly definable problem set?
2) What makes business applications not highly definable problem sets?
3) What makes business applications complex and changing?  And the
middleware problem space isn't changing?
4) In what possibly way is OOP "in general" a bad idea where the problem
set is complex or changing?  That seems like the ideal environment for the
OOP paradigm.

As soon as a problem becomes complex or requires frequent change, that's
exactly when I want an OO language.
Sorry, dude... I encourage you to explain further, but right now, I just
don't get it.

Richard D. Dettinger
iSeries Java Data Access Team

Democracy's enemies have always underestimated the courage of the American
people.
It was true at Concord Bridge.  It was true at Pearl Harbor.  And it was
true today.

         Rochester Post-Bulletin
         Tuesday September 11, 2001


|---------+---------------------------->
|         |           "Joe Pluta"      |
|         |           <joepluta@PlutaBr|
|         |           others.com>      |
|         |           Sent by:         |
|         |           java400-l-admin@m|
|         |           idrange.com      |
|         |                            |
|         |                            |
|         |           09/17/2002 10:25 |
|         |           AM               |
|         |           Please respond to|
|         |           java400-l        |
|         |                            |
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  |       Subject:  RE: Java versus RPG on iSeries                              
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> From: Chris Hanisch
>
> I am investigating the possibilities of creating Java applications on the
> iSeries and replacing some of the RPG applications.  I was wondering if
> anyone else has had experience in replacing RPG with Java on their
iSeries
> and what some of the advantages and disadvantages are.

Chris, I've been using Java for a long time now, and it is my firm opinion
that Java is not the right tool for business application development.  RPG
is still the best language for any non-trivial business applications,
because of its direct integration with OS/400 and DB2/400.  Java adds a
level of indirection both in its program architecture (via the JVM) and its
database access (which I assume will be JDBC in your case).

> 1) Run Time/Performance.  Can Java be just as quick as sensible to use
for
> Interactive and Batch Programming ?

No.

> 2) Is it sensible to still use Green Screen with Java and slowly convert
> over to GUI interfaces ?

No.

> We are in need of developing a green screen
> application using Java to show that Java can do the exact same
> thing as RPG.
> Anybody know how easily this can be done or provide some sample code ?

No.

> 3) Are the advantages significant enough to warrant migration to
> Java on the
> iSeries ?

No.

> If anyone has some information/experience on dealing with this,
> it would be
> greatly appreciated.

As I said, I've done a lot of Java programming for the iSeries.  I've
written and taught extensively on the topic, and I believe that Java (and
to
a lesser degree OOP programming in general) is best suited to highly
definable problem sets, such as middleware, and less suited to complex,
changing requirements such as those found in business applications.

I have seen very few successful business application implementation on any
platform, much less the iSeries, which already has not one but two built-in
business languages, COBOL and RPG.

Joe

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