log4j and java.lang.NoClassDefFoundError: org/apache/log4j/Layout

Question

I am trying to get a piece of code working with log4j. If I run it via junit tests (ant task), I am getting proper log outputs and all is fine. If I run the code from the command line, I get this:

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/log4j/Layout
        at uk.co.bytemark.flexnbd.Main.main(Main.java:29)
Caused by: java.lang.ClassNotFoundException: org.apache.log4j.Layout

I tried the two following classpaths but neither helped. The error remains.

  export CLASSPATH=/home/yann/java/apache-log4j-1.2.16/log4j-1.2.16.jar 
  export CLASSPATH=/home/yann/java/apache-log4j-1.2.16/

Even with this

$ java -cp /home/yann/java/apache-log4j-1.2.16/log4j-1.2.16.jar -jar ./dist/lib/flexnbd-`date +%Y%m%d`.jar server ::1 12345 fileSystem
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/log4j/Layout
        at uk.co.bytemark.flexnbd.Main.main(Main.java:29)
Caused by: java.lang.ClassNotFoundException: org.apache.log4j.Layout
        at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
        ... 1 more
$ ls -ld /home/yann/java/apache-log4j-1.2.16/log4j-1.2.16.jar
476K -rw-r--r-- 1 yann yann 471K Mar 31 05:16 /home/yann/java/apache-log4j-1.2.16/log4j-1.2.16.jar

Any idea what I am doing wrong?

Solution

Found the problem. If you use -jar, your CLASSPATH is ignored. A better command line is thus:

java -cp dist/lib/flexnbd-20100716.jar:/home/yann/java/apache-log4j-1.2.16/log4j-1.2.16.jar uk.co.bytemark.flexnbd.Main [...]

Thanks for the help!