I have a requirement where I need to run a helloworld java program in unix environment for every 30 mins.
1. I am using crontab utility for this
purpose.
2. My cronfile looks like
0,30 * * * * java helloworld

3. Now when try to run following command,
"crontab cronfile"
I got an error saying java not found.

Now the question is how to set the environment variable to run crontab?

Thanks,
Naga

Naga,
If you run "java helloworld" interactively with no problems, then your session has a PATH that can find java. If you do "which java", it will tell you which executable it is finding.
A cron job running as a certain user does not execute that user's .profile, so it does not get the same environment established as your interactive session. You could change your cron entry to a fully-qualified java:
0,30 * * * * /opt/java/bin/java helloworld
but I think you will have other environment variables to consider. So have cron run a script instead of a single command:
0,30 * * * * myjavascript
and myjavascript will be something like:

#!/sbin/sh
PATH=$PATH:morepathstuff
CLASSPATH=whatever
java helloworld
echo `date` finished >> myjavascript.log

The cron job will run in the user's home directory, which is where I am assuming that helloworld is located.

James

hello,
i am not still able to solve the problem of crontab as suggested by you(ie how to run a java program from crontab entry)
Can u please elaborate on ur answer..i will be grateful

regards
amit