Re: RPGIV to Java prototype/call miss-match

Christen, Duane wrote:

We're at 6.1.

With the enhancements to RPGIV thread handling in 6.1 I tested
another Java interface process with and without *SERIALIZE and found
no problems with the results but performance of the process without
*SERIALIZE was much better.

This may bite me later, but I have a note in the production source as
to the reason Thread(*SERIALIZE) is not set and a caveat to put it in
if problems occur.

I don't know that leaving Thread(*SERIALIZE) off is "good" or "bad"
but it seems to work. I assume someone (Scott? :)) will tell me if I
am being foolish in my assumptions.

The enhancements to RPGIV thread handling provide another way to be threadsafe by coding THREAD(*CONCURRENT). They don't have any effect at all if you don't code the THREAD keyword. If you haven't coded any THREAD keyword at all, and your RPG code does ever get called from multiple Java threads at once time, then you will not be threadsafe.

I wouldn't code THREAD(*CONCURRENT) unless I knew for sure that my RPG code was going to run multi-threaded, and even then, I might code THREAD(*SERIALIZE).

When there is a possibility of running multi-threaded, the THREAD keyword should be coded. But remember that coding the THREAD keyword only provides thread-safety for the static storage in your RPG modules. It doesn't actually make you thread safe; there are other thread-safety issues that you have to consider.

If the Java code you're calling can never call back into your native code, you might be ok not coding the THREAD keyword. But it's not a valid test to just try your application without the THREAD keyword and if nothing goes wrong, assume it's ok. If you did happen to become multi-threaded in your native code, there's no guarantee that any one test run would expose a possible thread-safety issue. (Compare to a driver who says they have tried ignoring the red lights at that intersection, and it seems to be ok.)

So, some analysis is needed to determine whether you need the THREAD keyword or not.