Re: Calling a java pgm from RPG IV

["Blair Wyman" <blairw@xxxxxxxxxx>]

Fred's description is tremendous, as usual.  I'd just add a couple of
points.

First, the JVM *is* changing to use so-called 'system threads.'  In theory,
this could facilitate use of the JNI invocation API directly on-process,
instead of requiring a SBMJOB.

Next, I'm not an RPG expert, and I don't play one on TV, but my
understanding is that RPG can only be used as a native method
implementation language when the "big hammer" of module-level serialization
is employed.

There is an 'H-spec' THREAD(*SERIALIZE) that creates a mutex at the module
level.  Before any code in a module can execute, it first obtains its
module's mutex.  This really goofs up multi-threading, and effectively
makes every RPG native method a sort of perverted "static synchronized"
critter, regardless of its definition to Java.

COBOL has the same restriction, AFAIK, so for native methods the right
answer is C or C++, IMO.

HTH.

I love acronyms.

-blair

Blair Wyman -- IBM Rochester -- (507) 253-2891
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"The first principle is that you must not fool yourself -
  and you are the easiest person to fool."   -- Richard P. Feynman

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