Cron job for a Java Program

Question

I am using a java program which sends email after finishing up some file transfers.I am using Eclipse to code up the program. How do I set up a cron job to execute this java

Answer 1

r0ast3d has a quick, clear answer - I did have to do some more searching to get each step done so I'll elaborate on his steps:

1. Write a shell script to invoke your java program with the necessary arguments. Example:

   !/bin/bash
   echo "Running script."
   cd ~/your/classpath/to/java
   java -classpath .:somejar.jar path/to/your/Program
   

   Separate your necessary classpaths with colons (:) rather than semicolons (;) The path to your program should start with your package (find this at the top of the java program)

2. Make sure that the classpath argument points to the jars that you need. You can check your import statements in your java program to make sure you are specifying all the necessary classpaths. You have to run this script from your java directory, and can use a single period (.) as your first classpath argument.

3. Make sure that the shell script has necessary unix permissions.

   Run from a terminal: sudo chmod ### yourScript.sh

   Where ### are numbers representing the correct permissions for your system setup.

4. Schedule the script to be invoked by setting up a cron job.

   Run from a terminal: crontab -e

   This will open your crontab editor. You can add a job in this way:

   */5 * * * * bash /home/scripts/yourScript.sh

   Replace the path to the script with the correct location of your script. This job is set to run every 5 minutes. See http://www.adminschoice.com/crontab-quick-reference/ for a good reference on crontab.

Hope this helps someone out!

Answer 2

There is the cron4j library http://www.sauronsoftware.it/projects/cron4j/. I have used it before to schedule a java program to run weekly. The scheduling syntax is the same as a crontab. The thing is, it needs to be constantly running as a background process to work. I ended up just using normal cron, but it could be useful if you're not on an Unix-like system, and you don't have cron.

Answer 3

• Write a shell script to invoke your java program with the necessary arguments.
• Make sure that the classpath argument points to the jars that you need.
• Make sure that the shell script has necessary unix permissions.
• Schedule the script to be invoked by setting up a cron job.

For more info about cronjob look here http://en.wikipedia.org/wiki/Cron

just my 2 cents...

Answer 4

use quartz for more complex need or Timer for a simpler task