Re: "Attaching Java program to ..." ???

Hi David,

I found the excerpt below from "V5R4 Performance Update GOP02" at:

http://www-304.ibm.com/jct01004c/systems/support/i/library/techoverviews/v5r4/pdf/v5r4performance.pdf

Notice that it's somewhat different than what we were told in "With V5R2,
the JIT Compiler Comes of Age" at

http://www.ibmsystemsmag.com/print/print.aspx?print_page=%2Fi5%2Fseptember02%2Fdeveloper%2F8100printp1.aspx&string_referer=/i5/september02/developer/8100p5.aspx


The Excerpt:

"Java Performance and JIT versus DE

Starting with V5R3, JIT is always recommended for best performance of 32-
bit (no DE) or 64-bit Direct Execution (DE) is the default for 64-bit JVMs,
unless:

- ADDENVVAR ENVVAR (JAVA_COMPILER) VALUE(jitc) JAVA CLASS(Test)

- OR Create your Java programs under:

Either Set java.compiler system property on the i5/OS command line ->
JAVA CLASS(Test) PROP((java.compiler jitc)) or

Set the java.compiler system property on the Qshell Interpreter command
line. For example, enter java -Djava.compiler=jitc Test

Even if running JIT, the JVM will have to create a Java program object (with
optimization level *INTERPRET) the first time a particular Java class is
used on the system, if one does not already exist.

-Creation of this program object is much faster than creating a
full DE program, but it may still take some time

-Running CRTJVAPGM with OPTIMIZE(*INTERPRET) will create this
program ahead of time, making the first startup faster"


Joe Sam

Joe Sam Shirah - http://www.conceptgo.com
conceptGO - Consulting/Development/Outsourcing
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----- Original Message ----- From: "David Gibbs" <david@xxxxxxxxxxxx>
To: "Java Programming on and around the iSeries / AS400"
<java400-l@xxxxxxxxxxxx>
Sent: Friday, February 22, 2008 3:28 PM
Subject: Re: "Attaching Java program to ..." ???

David Gibbs wrote:

When I run my some java code on the System i, I get a 'Attaching Java
program to <name of jar>' displayed in a terminal session.

I opened up a PMR with IBM about the issue ... was told:

On the i5/os, there needs to be *pgm objects, Static compilation, (glue
code) to crtjvapgm objects. The messages you see are necessary on i5
platform.

AFAIK, this is not the case when using the JITC compiler.

Can anyone confirm or refute this?

Thanks!

david

--
IBM System i - For when you can't afford to be out of business

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