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From C G <parallel...@yahoo.com>
Subject Newbie question...with appropriate apologies in advance...
Date Thu, 26 Jul 2007 22:00:23 GMT
I've deployed hadoop-0.13.0 and successfully run some examples.  Now I am trying to compile
and run the examples prior to starting to develop my own code.  I've managed to do little
more than get a nice spew of error messages.  This is no doubt due to my own ignorance and
too much Python programming, but can anybody tell me how to compile the examples (WordCount.java
for example) and run them?
  I apologize for the basic question, which I am sure is classpath-magic related.  Any assistance
most appreciated.  I promise to be helpful to other newbs like myself going forward.
  I've tried a bunch of stuff, but it all comes down to various "can't find class X' errors.
 This is representative of as far as I've gotten:
  % java -version
  java version "1.6.0_02"
Java(TM) SE Runtime Environment (build 1.6.0_02-b05)
Java HotSpot(TM) Client VM (build 1.6.0_02-b05, mixed mode, sharing
  % cd ${HADOOP_HOME}/hadoop-0.13.0/src/examples/org/apache/hadoop/examples
  % javac -classpath ${HADOOP_HOME}/hadoop-0.13.0/hadoop-0.13.0-core.jar WordCount.java
  % jar -cvf WordCount.jar *.class
  % cp *.jar ${HADOOP_HOME/hadoop-0.13.0/
  % cd ${HADOOP_HOME/hadoop-0.13.0/
  % bin/hadoop jar WordCount.jar WordCount input_files/text.txt output_files/results2.txt
Exception in thread "main" java.lang.NoClassDefFoundError: WordCount (wrong name: org/apache/hadoop/examples/WordCount)
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:620)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
        at java.net.URLClassLoader.access$000(URLClassLoader.java:56)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
        at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:247)
        at org.apache.hadoop.util.RunJar.main(RunJar.java:148)

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