Weka ClassNotFoundException

2
votes

I'm attempting to install Weka, which I have installed into /weka directory. I set the CLASSPATH variable, but that shouldn't matter anyway because I'm using -cp.

I enter this into SSH:

java -Xmx5G -cp /weka/weka.jar weka.core.converters.TextDirectoryLoader -dir /home/myuser/test > /home/myuser/test.arff

And it spits out:

Exception in thread "main" java.lang.NoClassDefFoundError: weka/core/converters/TextDirectoryLoader Caused by: java.lang.ClassNotFoundException: weka.core.converters.TextDirectoryLoader at java.net.URLClassLoader$1.run(URLClassLoader.java:217) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:205) at java.lang.ClassLoader.loadClass(ClassLoader.java:321) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294) at java.lang.ClassLoader.loadClass(ClassLoader.java:266) Could not find the main class: weka.core.converters.TextDirectoryLoader. Program will exit.

What wrong? There is no "weka/core/converters/TextDirectoryLoader" because its all stored in weka.jar, which is where it should be looking.

My Java version:

java version "1.6.0_20" OpenJDK Runtime Environment (IcedTea6 1.9.10) (rhel-1.23.1.9.10.el5_7-x86_64) OpenJDK 64-Bit Server VM (build 19.0-b09, mixed mode)

I just downloaded Weka today from the link on their downloads page, so there shouldn't be anything wrong with it.

Now I know that this would normally be because it can't find weka.jar, but I promise you that it is right there at: /weka/weka.jar. And I can also promise that both the /weka directory and weka.jar have execute permissions.

Please help!

2
javanoclassdeffounderrorwekaclassnotfoundexception
It's non-existent! I decided to go ahead and unpack the jar file and there is no weka/core/converters/TextDirectoryLoader.class! What happened there? Everyone else seems to have it. – Alasdair

2 Answers

2
votes

Just downloading and running the .jar works for me:

carsten@dallas:~$ java -Xmx5G -cp /tmp/weka-3-6-5/weka.jar weka.core.converters.TextDirectoryLoader

Usage:
  TextDirectoryLoader [options]

Options:
...

as well as java -jar /tmp/weka-3-6-5/weka.jar, which opens some GUI tool.

You sure that you installed Weka on the server you SSH into?

0
votes

I happened the same to me in Mac OS when I used the jar released in the dmg packaged.

Instead of that one, I imported the jar file under:

Applications/Weka/Resources/java/weka.jar

To get it you have to:

  1. go to Applications
  2. right click over weka-3-x-x
  3. Show package content
  4. go to /Resources/java/weka.jar
  5. import that one jar into your classpath