RE: Overhead/downsides to JVM in each job (was: JVM properties -a ngst)

When it is likely that the RPG app which employs java classes will be
called while servicing a web based request then the overhead of JVM
startup is not necessarily much of an issue where each thread of the
HTTP server persists to service many requests

Agreed. Whether it's in a app server like websphere, or used
server-side via RPG in a CGI environment the JVM startup is a non-issue.

When launching a server-side java app (from RPG or otherwise), I run an
initialisation process prior to receiving asynchronous requests. Not only
does this take care of starting JVM but also to establish connection to
external resources such as DB2 or a queue object.

For versioning, I set this environment variable at *SYS level
QIBM_RPG_JAVA_PROPERTIES = '-Djava.version=1.4;'

Hmmm... I suppose we could do that, would it be version 1.5 or 5.0? :)

'-Djava.version=1.5;' Can also set at job level if concern regarding
version conflict.

Also consider setting version via SystemDefault.properties file.
Adding as 'java.version=1.5' Can be set at either system or user profile
level.

I would suggest that green screen JVM use is horses for courses.

This is green screen. When a programmer wants to use a specific command
we're calling a remote web-service to open a ticket in Remedy (issue
tracking system) to track the usage request. Since many programmers
could be using this command we decided it was better to centralize the
JVM to one task than have each programmer have a JVM active.

Agree. But could have requirement to run several sever jobs each servicing
hundreds of web or call centre clients. So, as mentioned earlier, better to
run in a dedicated subsystem.


Also, if the java processes run as multi-thread and are called from RPG then
they are unsupported from an interactive job anyway.....

Keith



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