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From Zhengguo 'Mike' SUN <>
Subject Re: LanczosSolver and ClassNotFoundException
Date Tue, 22 Feb 2011 03:11:21 GMT
OK. I gave up on my code and switched to run some example code from Mahout. I ran the clustering
example from quickstart as follow:
bin/hadoop jar ../trunk/examples/target/mahout-examples-0.4-SNAPSHOT.job org.apache.mahout.clustering.syntheticcontrol.canopy.Job

Again, it worked on my local machine and gave me ClassNotFoundException in the cluster.
java.lang.RuntimeException: java.lang.ClassNotFoundException: org.apache.mahout.clustering.syntheticcontrol.canopy.InputMapper
at org.apache.hadoop.conf.Configuration.getClass(
at org.apache.hadoop.mapreduce.JobContext.getMapperClass(
at org.apache.hadoop.mapred.MapTask.runNewMapper(
at org.apache.hadoop.mapred.Child.main(
Caused by: java.lang.ClassNotFoundException: org.apache.mahout.clustering.syntheticcontrol.canopy.InputMapper
at Method)
at java.lang.ClassLoader.loadClass(
at sun.misc.Launcher$AppClassLoader.loadClass(
at java.lang.ClassLoader.loadClass(
at java.lang.ClassLoader.loadClassInternal(
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(
at org.apache.hadoop.conf.Configuration.getClassByName(
at org.apache.hadoop.conf.Configuration.getClass(
... 4 more

From: Sean Owen <>
To: Zhengguo 'Mike' SUN <>
Cc: "" <>
Sent: Monday, February 21, 2011 3:34 PM
Subject: Re: LanczosSolver and ClassNotFoundException

In contrast, what is the scenario where it didn't work then?
This may be a dumb question that a Hadoop guru would know better. occurs in the... master? but not on the "client side". I
don't know why the classpath would be different though, but, this is
the essential issue.

(I've not seen this ever.)

On Mon, Feb 21, 2011 at 7:52 PM, Zhengguo 'Mike' SUN
<> wrote:
> Yes. I put the .jar files under the lib/ directory of my own jar. I didn't
> set the Class-Path in MANIFEST.MF in the past. I just tried putting all jar
> files in the Class-Path of MANIFEST.MF, it still gave me the same exception.
> My experiment is a little bit different. It creates a Vector in the map
> function of the Mapper class. It worked correctly in the cluster.

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