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From Marcin Biczak <>
Subject Re: java.lang.ClassNotFoundException for VertexOutputFormat
Date Fri, 09 Nov 2012 13:05:51 GMT
Hi again

I have found a solution to my "problem". I simply added myJobs.jar to the
HADOOP_CLASSPATH. Also "-libjars" parameter is not needed any more. But it
still puzzles me why the previous "solution" "suddenly" stopped working (I
haven't update the giraph revision etc).

HADOOP_CLASSPATH contains girpah.jar and myJobs.jar


2012/11/8 Marcin Biczak <>

> Hi
> I have very strange problem regarding ClassNotFoundException for vertex
> output format (my own implementation). When I run my program I get an
> exception:
> java.lang.RuntimeException: java.lang.RuntimeException:
> java.lang.ClassNotFoundException:
> org.test.giraph.utils.writers.generic.SamplingOutputFormat
>         at
> org.apache.hadoop.conf.Configuration.getClass(
>         at
> org.apache.giraph.graph.BspUtils.getVertexOutputFormatClass(
>         at
> org.apache.giraph.bsp.BspOutputFormat.getOutputCommitter(
>         at org.apache.hadoop.mapred.Task.initialize(
>         at
>         at org.apache.hadoop.mapred.Child$
>         at Method)
>         at
>         at
>         at org.apache.hadoop.mapred.Child.main(
> I have came across this exception earlier and I've solved it with the use
> of "-libjars" parameter in which I pass the path to
> giraph-0.2-SNAPSHOT-jar-with-dependencies.jar and myJob.jar (which I
> execute). This solution has worked very nice for me, I used it in a number
> of programs (with my own InputFormat and OutputFormat), till today. I've
> created a small program (TestVertex) to test one solution and I used a
> NewOutputFormat created for the test program. When I received
> ClassNotFoundException I thought I have made a mistake somewhere, so I've
> checked. I couldn't find any bugs, so I replaced the NewOutputFormat with a
> one used across other programs (OldOutputFormat). I got the same exception.
> for the old one as well. I have cleaned and build the whole myJob.jar and I
> was still getting the exception (both for New and Old). So I tested the
> original program (same myJob.jar) in which I'm using the OldOutputFormat
> and the program works. Since then I tried couple of OutputFormat and none
> of them worked (ClassNotFoundException). Then I commented the whole "body"
> of TestVertex and I've paste some old working code (with OldOutputFormat).
> The only difference between TestVertex and old working code is the class
> name. Final I received the ClassNotFoundException again (again the original
> code works, I've tested it). It looks like only the TestVertex class has
> this problem, no matter what OutputFormat I will use I am always getting
> the exception (all other programs which use my OutputFormats work
> correctly).
> Another interesting aspect is the fact that if I use Giraph provided
> OutputFormat (for example JsonBase64VertexOutputFormat) I get a
> ClassNotFoundException but for the TestVertex. I've checked the myJob.jar
> and all mentioned classes are present in the jar in correct places.
> I run out of ideas any suggestions will be greatly appreciated.
> Some conf info
> I am using an older Giraph revision (1340869) and Hadoop 0.20.203 in
> pseudo-distributed mode.
> I have created the HADOOP_CLASSPATH which holds path to
> giraph-0.2-SNAPSHOT-jar-with-dependencies.jar.
> I execute job in the following way: hadoop jar myJob.jar
> org.test.giraph.Test -libjars
> /path/to/giraph-0.2-SNAPSHOT-jar-with-dependencies.jar,/path/to/myJob.jar
> /path/to/input /path/to/output <job params>
> regards
> marcin


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