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# 1  
Old 11-15-2002
Question java errors when calling from cron

I am more or less new to using cron, and I am trying to automate a log cleaning system I have made. The system basically cleans through WWW logs that are mounted on an NFS and creates text files for entry into a local PostgreSQL DB.

For the past year I have been running the various scripts and programs I have created from the terminal daily. Everything worked just fine. However, when I rely on cron I now I find I can not insert into my PostgreSQL DB using its JAVA interface. I get the following errors:

Exception in thread "main" java.lang.NoClassDefFoundError: /Users/admin/LOGS/Insert_data

The flow of the insert routine that I use runs as follows:

01_insert_data.csh -> 01_insert_data.pl -> Insert_data.class
(call one site at a time) (lists up non-inserted files) (inserts data into DB)

What is the difference between running appli from the terminal and running appli from the cron? What gets "lost" with cron that would be nomally found on the terminal?
# 2  
Old 11-16-2002
May be as simple as not using absolute paths or not exporting env. variables

most differences in behavior we see between cron running a job and manual runs is because of differences in path setting...

it is always imperative to use absolute paths (starting from /) in all the directory paths in your script...

similarly I hope that you export all the relevant environment variables (like PATH etc) in the very beginning of your shell script... if you run a script manually it will inherit all the env. variables of your logon shell (some of them may be set in your .profile).. if you run a script using cron it will inherit all the cron user's env. variables... you need to ensure within the script that all required env. variables are explicitly set and exported, so that these hold the same values for the subsequent commands using them - both in cron and manual modes...

the java exception you show indicates that a java class was not found in the class path...

Hope this helps...

Cheers!
Vishnu.
# 3  
Old 11-17-2002
Vishnu

Thanks for the info. I dealt with the absolute path bit as soon as I had run the script one time, so absolute paths should not be the issue here anymore...that is unless I have overlooked something.

I am now working on the env. variables bit. I have tried all sorts of combinations - put information concerning java's home into both CLASSPATH and PATH. I have set CLASSPATH and PATH in .tcshrc as well as in the sell script that starts everything moving. Yet I end up with the same error.

It's really a bit frustrating! So, what I have decided to do is create a HELLO WORLD java program and call it directly from the C shell, eliminating for the time being perl which enters the picture between CSH and JAVA in the log cleanning set up I am trying to run from cron.

m(_ _)m
# 4  
Old 11-18-2002
Bug Just a bit of follow up...

I had been under the impression that trouble I encountered when trying to run my Insert_data JAVA class(application or whatever) can from my shell's ENV not being set correctly. I tried everything! I set CLASSPATH and PATH in .tcshrc . In the initial C SHELL script that is called from cron, I added things like ...

setenv JAVA_HOME_R "/System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK/Classes"
set classpath=($JAVA_HOME_R/classes.jar $JAVA_HOME_R/postgresql.jar)

You name it I tried it, but nothing worked.

What I found was it had nothing to do with setting my shells ENV (i.e. PATH CLASSPATH and such). Instead, this turned out to be entirely a JAVA side problem/solution. It was as simple as the following.

java -classpath /Users/admin/LOGS Insert_data

With the above I can run Insert_data from any directory on my machine, and I also have no trouble running/calling from cron.

Problem solved. Sorry to have gotten away from the main topic of discussion here, but I felt it might save others time, perhaps, to give a follow up.

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