A couple of thoughts to get the discussion going...
I'm probably biased because the more I use Java, the more I like
that programming language. At first, it looks somewhat similar
to C, but fortunately, it is very different (in a positive way).
I like the language design and the rich class libraries, which
sometimes help being more productive. Object oriented programming
is quite different from the procedural approach, so it does have
a learning curve.
A nice aspect of Java on or for the 3000 is that you can probably
draw from a new pool of potential programmers. In addition to that,
Java might be an interesting add-on for COBOL and other "legacy"
language programmers (old dog, new tricks).
Java is very handy in areas like GUI or network programming as
well as interoperability. Notice that you can use Java with your
3000 either on the client side only, on the host side, or both.
I have wrapped "legacy" language programs with a Java client or
applet GUI, for example, without using any Java on the HP 3000.
I probably wouldn't scrap my old COBOL or Transact or whatever
"legacy" code and try to rewrite it in Java. This would probably
not have positive impact on performance, efficiency and cost. In
my opinion, it seems to be ideal to marry the strenghts of Java
and the legacy tools and languages. Despite all the benefits of
tools and technologies coming from the Posix and Freeware side,
the 3000 should probably not attempt to be a better Unix box.
Java opens a number of new technologies to the 3000 due to its
cross-platform nature. Examples like Java web or application
servers (Jigsaw, Apache JServ, Tomcat, Enhydra...) with servlet
and/or JavaServerPage capabilities run on MPE/iX without even
having to recompile. Other examples are access to LDAP servers
via JNDI (Java Naming and Directory Interfaces) or XML parsers
like xml.apache.org's Xerces. Even CORBA might be "in reach",
however, I have not played with that myself.
Or think of JDBC (Java Database Connectivity), which -unlike
ODBC- allows the 3000 to either act in an SQL database server
or client role (or both). The client part provides access to
Oracle or SQL Server databases on other platforms, for example.
One nice aspect of Java's platform neutral nature is that it
does not force you to use Microsoft Windows on the client side.
It does not "exclude" Linux or Mac users, for example.
Another aspect of the cross-platform nature is that you can use
a PC or laptop to develop programs (eg web or GUI front-end with
database access via JDBC) and later deploy (parts of) it on the
3000 or connect it to an Image/SQL or Allbase database.
Or you can start deploying on the 3000 and later decide to offload
parts of the application (eg web server and/or servlet engine) from
the 3000 to other platforms (eg dedicated NT or Linux server) for
load-balancing, scaling, or security reasons (firewall etc). Seems
to give quite some flexibility.
When getting my feet wet with Java on the 3000, I'd probably try
to start small and grow over time. First of all, it helps getting
practise and experience. Also keep in mind that Java/iX has not
yet been exercised as much as COBOL and other "legacy" languages,
so there is a higher risk of finding bugs in compiler or runtime.
In this regard, it pays off to use Open Source or home-grown code,
because this helps isolating problems, if they should occur. Notice
that debugging Java (on MPE) is not as convenient as native language
programs due to the current lack of debuggers. While the powerful
MPE/iX System Debugger is very helpful with native code, it doesn't
help too much when debugging (interpreted or JIT-ed) Java programs.
Hmm. So much as a first shot. Maybe others can chime in.
Lars.
(http://www.editcorp.com/personal/lars_appel/ -> Java Tips & Examples)
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