Can the JIT be turned off in JavaSE 5?

[Basler Mark]

Thanks Tom!!

That is exactly what I was looking for...

Thanks again - Mark :-)

--- On Fri, 4/24/09, Tom Rodriguez <Thomas.Rodriguez at Sun.COM> wrote:
From: Tom Rodriguez <Thomas.Rodriguez at Sun.COM>
Subject: Re: Can the JIT be turned off in JavaSE 5?
To: markabasler at yahoo.com
Cc: hotspot-runtime-dev at openjdk.java.net
Date: Friday, April 24, 2009, 3:31 PM

Hotspot still respects the -Djava.compiler=NONE as a request to disable the JIT.

% java -server -Djava.compiler=NONE -version
java version "1.6.0"
Java(TM) SE Runtime Environment (build 1.6.0-b105)
Java HotSpot(TM) Server VM (build 1.6.0-b105, interpreted mode)

Note that it says interpreted mode which means that the JIT is disabled. 
Normally it would report "mixed mode".

tom

On Apr 24, 2009, at 1:55 PM, Basler Mark wrote:

> Hi Guys,
> 
> I am having trouble finding whether the JIT is always on in JavaSE 5 or
that it can still be turned off by using
"-Djava.compiler='NONE'".
> 
> I want the JIT on, but I just found a script that is being used in a
legacy system that has this setting and I want to see if it matters anymore...
> 
> I did find an excerpt in "Java in a Nutshell" that states:
> "This environment variable and property are no longer used as of Java
1.4, which uses the HotSpot VM, which includes efficient JIT technology."
> 
> I have been looking around on the java.sun.com site and found references
to -Djava.compiler in the following places...
> 
>
http://java.sun.com/javase/6/docs/technotes/guides/jni/spec/invocation.html
> http://java.sun.com/javase/6/webnotes/6u4.html
>
http://java.sun.com/j2se/1.5.0/docs/guide/plugin/developer_guide/debugger.html
>
http://java.sun.com/j2se/1.5.0/docs/guide/deployment/deployment-guide/jcp.html
>
http://java.sun.com/developer/onlineTraining/Programming/JDCBook/perf2.html
> So I am really not 100% sure, either way...
> 
> Can someone who definitively knows let me know...
> 
> I also posted this on the Java forum at
http://forums.sun.com/thread.jspa?threadID=5382536&messageID=10689611#10689611
> 
> 
> Thanks for your help - Mark :-)

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