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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