[Info-vax] Java portability and VMS

[Arne Vajhøj]

On 17-02-2011 22:24, 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..."

They were also unfamiliar with various other platforms that Java runs on.

And Java is compiled - AOT to byte code and JIT to native.

> "...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..."

Opening a file with the name C:\test.txt on Unix does not
work well either.

Java does provide functionality to manipulate, split and combine
file name parts in a portable manner.

It is up to the programmer to use them.

The Java implementation for VMS seems to have been pretty
Unix oriented (whether that was because it is somewhat based
on SUN's *nix implementation or a choice to keep costs low
by having VMS and HP-UX versions close or both I don't know).

There are bunch of logicals to control the handling of files.

Some things can work on ODS-2.

But the least trouble approach is:
- use ODS-5
- use stream_lf files
- use *nix file name syntax with /

> "...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..."

Java threading seem to work fine on VMS. Java does not support fork.

So I don't understand this.

> 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 don't think so.

By:
- setting those file logicals correct
- using an ODS-5 disk
- giving the account huge quotas
- replace .sh/.bat startup and shutdown scripts with equivalent .com
then most should work unchanged.

JBoss AS is a pretty big app and it can be made to work
as described.

Arne