HADOOP :: java.lang.ClassNotFoundException: WordCount
classnotfoundexception, hadoop, java, mapreduce
Solution
If you're trying to run the wordcount provided in the examples, you should run:
hadoop jar hadoop*examples*.jar wordcount /home/temp/input /home/temp/output
More info on how to run wordcount on this link.
In general, if you're developing your own Map/Reduce jobs, you should include the full package name of your driver class, so something like this might work:
hadoop jar wordcount.jar com.something.WordCount /home/temp/input /home/temp/output
Problem
I am using eclipse to export the jar file of a map-reduce program. When i am run the jar using command ``` hadoop jar hadoop-prog.jar WordCount /home/temp/input /home/temp/output ``` it always shows the error : ``` Exception in thread "main" java.lang.ClassNotFoundException: WordCount 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 java.lang.ClassLoader.loadClass(ClassLoader.java:247) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:247) at org.apache.hadoop.util.RunJar.main(RunJar.java:149) ``` Btw, I get a sample example jar file of wordcount from internet and it ran very well. I could not figure out where is the problem.