Can the JIT be turned off in JavaSE 5?

[Tom Rodriguez]

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 :-)