Class Not Found exception in cron job

[Huw Morgan]

Hi,

I am not really a beginner, but I am fairly sure this is a simple question, and I am just missing something simple.

I am running a web server on a VPS. I want to check if there are any new files on the server and if there are, add some records to a database. I have writen a java app. and a script [1] that sets the CLASSPATH and runs the app. This runs fine from the command line, but fails when run as a cron job. I have writen a little test app. that demonstates the problem [2]. The exception is at [3] with some more debugging info from the script.

The jdbc jar file is in the right place [4].

Does anyone know what is going on here? If this belongs in a different forum let me know (or just move it).

Thanks for any help,

Hugh

[1] #! /bin/sh

whoami
echo $CLASSPATH
echo $PATH
CLASSPATH=/home/server/lib/mysql-connector-java-3.0.15-ga-bin.jar:.:/usr/local/jdk/lib/classes.zip:$CLASSPATH
PATH=/usr/local/jdk/bin:/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin:/usr/local/bin:/usr/X11R6/bin:/home/server/bin:$PATH
echo $CLASSPATH
echo $PATH
cd /home/server/public_html
/usr/java/bin/java TestClassLoader

[2]

import java.io.*;
import java.sql.Connection;
import java.sql.DriverManager;
 
class TestClassLoader 
{
 
    public static void main(String[] args)
    {
try {
    Class.forName("com.mysql.jdbc.Driver");
    String url = "jdbc:mysql://localhost/smsserver";
    Connection con = DriverManager.getConnection(url, "username", "password");
    con.close();
}
catch (Exception ex) {
    ex.printStackTrace();
}
 
    }
}

[3]

server
 
/usr/bin:/bin
/home/server/lib/mysql-connector-java-3.0.15-ga-bin.jar:.:/usr/local/jdk/lib/classes.zip:
/usr/local/jdk/bin:/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin:/usr/local/bin:/usr/X11R6/bin:/home/server/bin:/usr/bin:/bin
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
        at java.net.URLClassLoader$1.run(URLClassLoader.java:200)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:268)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
        at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:164)
        at TestClassLoader.main(TestClassLoader.java:10)

[4] [email protected] [~/public_html]# ll /home/server/lib/mysql-connector-java-3.0.15-ga-bin.jar
-rwxrwxrwx 1 server server 235712 Aug 7 13:17 /home/server/lib/mysql-connector-java-3.0.15-ga-bin.jar*

[ August 09, 2006: Message edited by: Huw Morgan ]
[ August 09, 2006: Message edited by: Huw Morgan ]

[Carl Trusiak]

I've seen this, check the permissions on the /home/server/lib/mysql-connector-java-3.0.15-ga-bin.jar and the folders leading to it. If the user that is running the Cron jobs doesn't have read permission on everything, you can get this.

[Huw Morgan]

As I posted in [4] above, I have put a copy of the .jar in a directory owned by the user "server", and it has all permisions (-rwxrwxrwx 1 server server 235712 Aug 7 13:17 /home/server/lib/mysql-connector-java-3.0.15-ga-bin.jar).

I have put whoami in the script, and this returns "server", so it must be that user who is running it.

[Ryan McGuire]

Is there a Driver class in that jar file? You sure?

Also, what gets printed for your path and classpath when you run the script from the command line?
[ August 09, 2006: Message edited by: Ryan McGuire ]

[Huw Morgan]

I solved the problem, I ran the app with;

java -classpath $CLASSPATH TestClassLoader

I still do not understand how this can fix it, but it will do for me.

The output of the script in in my OP. It is roughly;

#> whoami
server
#> CLASSPATH=/home/server/lib/mysql-connector-java-3.0.15-ga-bin.jar:.:/usr/local/jdk/lib/classes.zip:$CLASSPATH
#> echo $CLASSPATH
/home/server/lib/mysql-connector-java-3.0.15-ga-bin.jar:.:/usr/local/jdk/lib/classes.zip:

The jar file includes the driver.

[Trey Brown]

One thought on why your solution worked. It has been a while since I played with UNIX, but I seem to recall having a similar issue going from running a script manually to running it in the cron task. The issue, as I recall, appeared to be that the classpath was never picked up from the shell script by the java routine.

Try doing an "export" of the CLASSPATH environmental variable. I believe the issue came down to either a problem being allowed to set the environmental variable or the need for the CLASSPATH to be known outside of the shell.

[Ryan McGuire]

Exactly what Terry said.

CLASSPATH=/home/server/lib/mysql-connector-java-3.0.15-ga-bin.jar:.:/usr/local/jdk/lib/classes.zip:$CLASSPATH
PATH=/usr/local/jdk/bin:/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin:/usr/local/bin:/usr/X11R6/bin:/home/server/bin:$PATH
export CLASSPATH
export PATH
echo $CLASSPATH
echo $PATH

Without the export statements, the environment variables set in the shell script do make it into the JVM process.

If you were using bash, you could do the assignment and export in one command:
export CLSSPATH=blah blah blah

But with sh, you need the two separate lines.

From the man page for export:

SYNOPSIS
  sh
     export [name...]
 
DESCRIPTION
     With the export built-in, the given  names  are  marked  for
     automatic export to the environment of subsequently executed
     commands.  If no arguments are given,  variable  names  that
     have  been marked for export during the current shell's exe-
     cution are listed. Function names are not exported.