Thanks Lucas...I did run everything that way to test and evaluate. Now I'm
just trying to figure out how to build and deploy my own code.
Lucas Nazário dos Santos <[EMAIL PROTECTED]> wrote: Hello.
My reply is embedded with your text, marked with ###.
Cheers,
Lucas
On 7/26/07, C G
wrote:
>
> 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?
##########################################################
You don't need to compile the examples. They already come compiled for you
inside Hadoop's home folder, wrapped in the jar named
hadoop-0.13.0-examples.jar.
##########################################################
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)
##########################################################
Instead of issuing
% bin/hadoop jar WordCount.jar WordCount input_files/text.txt
output_files/results2.txt
try something like
% bin/hadoop jar hadoop-0.13.0-examples.jar wordcount input_files
output_files
Notice that you must copy your input files to HDFS, under the folder named
input_files (you can use bin/hadoop -put command). You also
musn't create the folder output_files, because Hadoop will create it
automatically for you. And don't forget to run Hadoop's tasktracker
(bin/hadoop tasktracker).
##########################################################
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