Question

I am trying to run this in pseudo distributed mode following the directions in Hadoop In Action. It ran when I used the local/standalone mode.

Now it can’t seem to find the path to the jar file.

cd $HADOOP_HOME


jps
17559 JobTracker
17466 SecondaryNameNode
17791 TaskTracker
16993 NameNode
17942 Jps

bin/hadoop hadoop-examples-1.0.3.jar wordcount

Warning: $HADOOP_HOME is deprecated.

Exception in thread "main" java.lang.NoClassDefFoundError: hadoop-examples-1/0/3/jar
Caused by: java.lang.ClassNotFoundException: hadoop-examples-1.0.3.jar
    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)
Could not find the main class: hadoop-examples-1.0.3.jar.  Program will exit.

My CLASSPATH is set to $HADOOP_HOME

Any ideas?

Answer 1

Two things that don’t look right:

1. You should also have DataNode process running check the logs to see what happened to it.

2. The correct command to use is bin/hadoop jar hadoop-examples-1.0.3.jar wordcount

3. You should also have HADOOP_CONF_DIR set to point to the directory with ‘hdfs-site.xml’ and ‘core-site.xml’