SAP JVM / SUN JVM

[Former Member]

Hi,

I was wondering about the SAP JVM. The document "What’s in the SAP NetWeaver Application Server, Java(TM) EE 5 Edition" states about "SAP's own Java VM features".

Cruising the filesystem of my Preview installation I was not able to find it. No sap.jar - files, additional copyright documentation or anything else.

Is it already part of the Preview Version?

Rgds

Markus

[Former Member · Accepted solution]

Hi Markus!

This version of NetWeaver as well as the IDE are already running on SAP's own JVM. You can find it in this directory: C:\SAP\JP1\_jvm

Best Regards,

Robin

[Former Member · Accepted solution]

Hmm ... all I get is:

java version "1.5.0_08"

Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_08-b03)

Java HotSpot(TM) Client VM (build 1.5.0_08-b03, mixed mode)

Can you give me some more hints on "differences" and "changes" and "modifications"? Is there additional documentation available?

Rgds

Markus

[Former Member · Accepted solution]

Hi Markus!

I think that the most important difference is the introduction of shared memory concepts for java objects in SAP JVM. If you want to read more about that and how it has impact on our server I suggest you to read the following article:

<a href="https://www.sdn.sap.comhttp://www.sdn.sap.comhttp://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/73a16f1d-0e01-0010-95a6-a4f66ca1a65e">Application Server's Robustness and High Availability</a>

Best Regards,

Robin

[Former Member · Accepted solution]

Thanks so far for your answers. I certaily already discovered the docs in sdn relating to this. I was hoping for some more details

[Vlado · Accepted solution]

Hi Markus,

Actually, the SAP JVM is located under C:\SAP\JP1\SYS\exe\run\sapjvm_5.

> Hmm ... all I get is:

>

> java version "1.5.0_08"

> Java(TM) 2 Runtime Environment, Standard Edition

> (build 1.5.0_08-b03)

> Java HotSpot(TM) Client VM (build 1.5.0_08-b03, mixed

> mode)

This is because you have also Sun's HotSpot installed and it appears earlier in your PATH variable. If you suppressed that, you would see:

java version "1.5.0_07"

Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_07-b00)

SAP Java Server VM (build 1.5.0_07-b00, Aug 29 2006 11:34:57 - BCO35 - opt - ext

ension version: 10 (mixed mode))

> Thanks so far for your answers. I certaily already

> discovered the docs in sdn relating to this. I was

> hoping for some more details

The most important features and benefits of SAP JVM include:

- Minimized memory footprint of an additional server node – achieved by the possibility to use byte code sharing and shared class loading

- Fast and reliable shared memory-based persistency for Java objects structures (for example, sessions)

- Faster way to handle Java serialization (via shareability concept)

- On-the-fly debugging and hot code replacement

- Shared memory-based monitoring of system resources (server processes, threads, sessions and so on)

If you would be more specific about what details you are interested in, probably our community could provide more comprehensive answers to your queries.

HTH!

-Vladimir