[Info-vax] Java portability and VMS

[Richard B. Gilbert]

On 2/17/2011 10:24 PM, Wendell wrote:
> I have been looking for info regarding Java on OpenVMS and
> portability. The only thing I found so far is here:
> http://h71000.www7.hp.com/openvms/journal/v10/javavms.pdf
>
> Some quotes:
>
> "...Java programs are much more portable than those written in a
> compiled language. However, we are still a long way from verifying
> total portability...The Java library creators, VM developers, and
> application developers are mainly from the UNIX world and, therefore,
> are unfamiliar with OpenVMS..."
>
> "...the majority of Java applications use file names that do not
> respect ODS-2 file semantics. If this is the case then it is vital
> that the file system be migrated to ODS-5 format..."
>
> "...Java ignores the notion of file versions..."
>
> "...The problems the Java developer encounters most often concern
> process management (such as fork, environment variables) and can be
> only resolved by modifying the source code and recompiling the
> application..."
>
> Of course, it always takes special care to write Java programs to be
> platform-independent, but this sounds like any significant application
> would require special porting to run on VMS. Is that true?

I suspect that a great deal depends on what you want to do.  "Hello 
world" will generally build in any language a platform supports.  Once 
you start writing code using features of the O/S and/or hardware 
platform you are locked into that hardware platform and/or O/S.

Doing a port from IBM/360 to H-P RTE-IV and then from RTE-IV to VMS 
taught me to avoid using non-standard language constructs or O/S and 
hardware dependencies.  It's not always easy to write portable code but 
if you do not write portable code it will sooner or later bite you in 
the ass!

If you want to find out just how much trouble your are in, make 
arrangements to get time on your target platform.  Then compile, link 
and run every bit of code you want to port.  It's almost certain that 
you will find programs that will not build or programs that will build 
but will not run correctly.

If the code you are trying to port was well written and well documented, 
porting may not be too difficult.  If the code to be ported was not well 
written and well documented  you may find that porting can be a real 
nightmare!

Porting a large body of code will make you a better programmer!

Good Luck!!  I'm quite certain that you will need it!