Simple Java Command Not Running in Cron

Question

We are trying unsuccessfully to run a java command in the following shell script:

#!/bin/bash
/usr/java/jdk1.8.0_91/bin/java -jar /home/cyberren/cyberren/cyberexe/D50_1_Migration.jar > d50Migration.log

We call it with the following line in our cron file:

45 08 * * * /home/cyberren/queries/d50migration.sh

We have confirmed that the shell script runs via cron, but it doesn't execute the java. It tries, but our log output is just this one line:

2016-Jun-30 08:58:11 - D50_1_Migration Process v104

We expect many more lines following such as this:

2016-Jun-30 08:58:11 - D50_1_Migration Process v104
2016-Jun-30 08:58:11 - migrateData -> SQL: UPDATE D50_1 SET xassessment = 192, iStepsTotal = 9 WHERE xIndx = 128
2016-Jun-30 08:58:11 - migrateData -> SQL: UPDATE D50_1 SET xassessment = 192, iStepsTotal = 9 WHERE xIndx = 129
...

We are able to run the same shell script manually, and it executes the java. We are also able to execute the java line manually, and it runs correctly.

So to repeat:

The cron job runs as scheduled
The shell script runs
The log is created, but only with the initial line
The java line in the shell script does not run
Both the shell script and the standalone java line run manually successfully
We have confirmed all directories referenced

Thanks in advance for the thoughts and advice.

Updates/Additional Info:

(Edit) Permissions are correct
(Edit) Tried adding a preceding cd "$(dirname "$0")" line per Alex's advice. Same output.

Solution:

@Jackson, you probably don't have access to the source code for the jar file, so debugging would be fruitless. Try setting up the cron job so that it is called from a bash login and sends STDERR output to STDOUT and logs both in a file, this should do it, 45 08 * * * /bin/bash -l -c "cd /home/cyberren/queries; ./d50migration.sh 2&>1 |tee -a /home/cyberren/d50migration.log" this way you should get to see all output and error output generated (if any) – Finbarr O'Brien 22 mins ago
At first we were pretty happy to have a way to look at our errors, but your cron line successfully ran the .jar! You've solved our problem and given us a way to successufully schedule and run java archive files via cron.

Hi ! You can try to add mode debug lines in your jar in order to see where it bugs — Jérèm Le Blond
– Jérèm Le Blond, Commented Jul 1, 2016 at 13:13
@Jägermeister Permissions are good! We confirmed with the same user via PuTTY. — Jackson
– Jackson, Commented Jul 1, 2016 at 13:17
@Jérèm Does it make sense that it would bug when run via cron but not when run manually? — Jackson
– Jackson, Commented Jul 1, 2016 at 13:18
Based on the fact that you get a line in the log, either the java program exits prematurely, or has hung somewhere. Are there any occurrances of the java process if you do ps -fu cyberren (assuming your user is 'cyberren')? I would suggest to try step debugging with your favourite IDE through the java code by adding debug parameters to the java command such as: -agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=7777 and see where it fails — Finbarr O'B
– Finbarr O'B, Commented Jul 1, 2016 at 13:20
Hint: never put more information into comments; update your question instead. — GhostCat
– GhostCat, Commented Jul 1, 2016 at 13:21

Finbarr O'B · Accepted Answer · 2018-09-14 09:10:48Z

4

Try setting up the cron job so that it is called from a bash login and sends STDERR output to STDOUT and logs both in a file, this should do it:

45 08 * * * /bin/bash -l -c "cd /home/cyberren/queries; ./d50migration.sh 2>&1 |tee -a /home/cyberren/d50migration.log"

this way you should get to see all output and error output generated (if any)

edited Sep 14, 2018 at 9:10

answered Jul 1, 2016 at 14:23

Finbarr O'B

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2 Comments

Jackson Over a year ago

Thanks again! Made an aggravating Friday into a nice start to the holiday weekend

pjd Over a year ago

I think it should be 2>&1 instead of 2&>1. (SO wouldn't let me edit only 2 characters in the answer.)

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