java.lang.NoClassDefFoundError when using weka.jar file in my own java file

Question

I'm having problems executing my java program. The code is placed in the file RunMining.java and contains multiple import weka.[..] lines. The weka library (weka.jar) is placed in the same folder.

I compile it:

$ javac -cp weka.jar RunMining.java

This creates three files: RunMining.class, RunMining$1.class, RunMining$classifierType.class

When i run it: java -cp weka.jar RunMining i get the following error:

Exception in thread "main" java.lang.NoClassDefFoundError: RunMining
Caused by: java.lang.ClassNotFoundException: RunMining
    at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)

My RunMining.java file only contains one class called RunMining, which contains the main method. I would prefer not to add the weka.jar file to my CLASSPATH since this file will be compiled using a makefile and executed using a script, on different machines. Any suggestions, to how i can run the compiled files?

Answer 1

You need to add the classpath of your compiled files as follows:

java -cp weka.jar;. RunMining

This assumes your files are compiled in the root directory which your javac command suggests.