Re: How hard is Java, really?

["Joe Pluta" <joepluta@xxxxxxxxxxxxxxxxx>]

> From: Dave Odom
>
> Thank you very much for your kind answer.   Just for the record, RPG was
> the first language I learned and I have had occasion to use it in years
> past.   RPG is a very good language in many respects.  My main problem
> with it is it is not a strategic/universal language like the others you
> mentioned (COBOL, C, Java, etc.).  Its localized to the i5.   But enough
> of that as I'm sure I'm not going to convert the faithful.

Gotcha.  If you're worried about being able to move your business logic,
then COBOL is certainly an option.  I've done quite a fair share of COBOL
especially recently and for the longest time I considered RPG to be
"shorthand for COBOL".  And while Java might be the language of people
coming from the lower end of the computing scale, mainframers are much more
likely to see 

However, the introduction of procedures gives RPG a fundamental edge over
COBOL at least as far as I know it.  COBOL has something called a
subprogram, I think, but I'm not familiar with it.  It may do for COBOL what

Procedures do for RPG, but I'm not certain


> You said: "I suppose you can do a poor second by using the record-level
> access
> functions within Java (and I get the impression that PHP might do the
> same)."
>
> Do I read you correctly that Java and PHP only do record-level access and
> not set level if needed?

See my response to Sean.


> You said:   "To be more precise, my favorite architecture is a thin JSP
> layer connecting
> to an RPG back end.  The majority of Java code in my preferred
> architectures
> is the generated code from the JSPs, with a relatively small amount of
> framework code to support them."
>
> This sounds like a superb architecture and I'm being sincere.  How do you
> generate code and what kind from JSPs?  What if I want to use another
> back-end language? Which one would you recommend and what are the
> advantages/disadvantages?

See my response to Nathan.  Basically, the JSP (which is HTML with Java code
interspersed) is converted entirely to a Java class and compiled just like
any other Java file.

The resulting class file is subject to the same loading, caching and JIT
compiling as any other Java class.  Thus if the JSP is a high-use JSP, it
will sooner rather than later be converted to machine code.  This can be a
significant advantage over templating methods which at best will cache the
template and then write the template out with substitution variables as
needed.


> BTW, do I understand you to have books out on some of this and/or classes
> (online or otherwise)?

I've written several books, one specifically on using a browser to replace a
green screen (E-Deployment, the Fastest Path to the Web).  And I teach these
techniques and mentor clients.

Joe