Re: Can I detect Java version before my java program starts? -- JAVA400-L

You bring up an excellent point.... The application is Tomcat (not theLPP version). Quite some time ago, it required tools.jar in theclasspath (I can't remember why). I just tried it without... and itseems to work. Guess I'll have to do some more testing.


Thanks for the link.



Dan Feather wrote:

I posted your question to the JT400 Support Forums and Jeff Lee there
posted this link:

http://publib.boulder.ibm.com/infocenter/iseries/v5r3/ic2924/index.htm?i
nfo/rzaha/sysprop.htm

And then check out the link near the top of that page for the "List of
Java system properties"

I think you can use the information found there to figure out what you
need to look at to determine what JVM is going to get used... since that
is how OS/400 will do it.

I am curious though why you need to add the tools.jar to the classpath?
That just seems odd to me.

Dan Feather

-----Original Message-----
From: java400-l-bounces@xxxxxxxxxxxx
[mailto:java400-l-bounces@xxxxxxxxxxxx] On Behalf Of TitanRebel
Sent: Thursday, August 04, 2005 12:44 PM
To: Java Programming on and around the iSeries / AS400
Subject: Re: Can I detect Java version before my java program starts?

Thanks for the suggestions and the logic!

Now, does anyone know of a way to determine which version is going to be

used? I don't think it automatically uses the highest version (am Iwrong?) It seems to be different based on version, release, andmodification of OS400.

I guess I could find out what the default is for each VRM of OS400 andadd logic to the script to take this into account. Then I would alsohave to look for the existance of .props files (I forget the locationand names right now) that could also determine which version is going to


be used.  I was just hoping there was an "easier" way to tell.

Thanks,

Ken


Bruce Jin wrote:

You can try these two methods:
1. In CL check the folder existence to decide if a particular JDKversion is installed. E.g. /QIBM/ProdData/Java400/jdk14 is the

location

of JDK 1.4.

2. If you call qshell scripts in CL you can check installed JDK usingsomething like this:

jdk14=/QIBM/ProdData/Java400/jdk14
jdk13=/QIBM/ProdData/Java400/jdk13
jdk12=/QIBM/ProdData/Java400/jdk12
if cd $jdk14
 then jv=4
elif cd $jdk13
 then jv=3
elif cd $jdk12
 then jv=2
else
 echo Connot find $jdk12 or $jdk13 or $jdk14!
fi
jdk=/QIBM/ProdData/Java400/jdk1$jv
echo Found JDK 1.$jv, use $jdk.
export -s JAVA_HOME=$jdk

I hope someone has better ways to do this.

Bruce