We Heart Code » linux

Capturing Uncaught Java Exceptions in a Bash Shell Script

Tim — Wed, 13 May 2009 16:53:28 +0000

I was burned one to many times by chaining dependent java programs together in a bash script.

By default the java executable will return zero if the program exited manually, and 1 if there was an uncaught RuntimeException.

Let's say test.sh runs a java program, we want to run it 3 times, but if it fails during any of the runs we want to abort our run.

#!/usr/bin/bash
java Test
exitval=$?
echo "exit val: ${exitval}"
exit $exitval

Then in our shell script to run test.sh each time we'd do something like this.

#!/usr/bin/bash

./test.sh
step1=$?

if [ $step1 -eq "0" ] ; then
./test.sh
step2=$?
if [ $step2 -eq "0" ] ; then
./test.sh
step3=$?
if [ $step3 -eq "0" ] ; then
echo "Finished successfully."
else
echo "Step 3 failed."
fi
else
echo "Step 2 failed with ${step2}"
fi
else
echo "Step 1 Failed. with ${step1}"
fi

To test my script I made a little java class that will error out half the time that looks like this:

import java.util.Random;
public class Test
{

public static void main(String[] args)
{
Random gen = new Random();
if(gen.nextInt(2)> 0)
{
System.out.println("I Win!");
}
else
{
throw new RuntimeException("I Fail!");
}
}
}

Bookmark to:

Killing a process by name in ubuntu

Tim — Mon, 17 Sep 2007 20:52:23 +0000

I have to kill mongrel alot because it's a flea-bitten mutt.

My usual method was to do a ps -aux | grep mongrel , find the pid and kill it!

Annoying and stupid!

Now I just use the nice pkill tool in ubuntu like so.

pkill mongrel

boom! All bad doggies killed! This probably works on other *nix flavors, but who knows if your stupid admin installed it.

Bookmark to:

Java App Empty Window under Compz-Fusion / Beryl

Tim — Sun, 22 Jul 2007 19:26:41 +0000

This weekend I was playing around with Ubuntu 7.04 and Compiz-Fusion, I didn't have any major problems until I tried to get Oracle SQL Developer and Aqua Data Studio to work, they would start up but no interface would be drawn.

Well the problem is that they were trying to figure out the Window Manager for themselves and failing.

To fix this add:

export AWT_TOOLKIT=MToolkit

to your bash profile/rc or just in the respective shell script of the app.

Now we can wobble our windows while we code :)

Bookmark to:

Great Alternative Oracle Site

Tim — Mon, 09 Jul 2007 12:45:01 +0000

During the last week or so I've been going through the process of setting up an Oracle 10g database on CentOS 4.5. Rather than relying on the toads at OTN or the raving throngs of confusion at the oracle.com forums for advice. I learned everything I needed to know at Dizwell Informatics. It's the site and blog of an Oracle DBA from down under who has detailed tutorials complete with annotated flash videos for everything you need to know to get an Oracle Database up and running. Here's the ones I used

Installing CentOS in VMWare.: For the practice run.
Installing Oracle 10g on CentOS: Great Article on all the pitfalls of the crazy oracle install.
Creating a Database with dbca
...and on and on.

Anyway, it's a great site with tons of articles and helpful forums and you get to save the shame from having to ask questions on metalink.

Bookmark to: