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From "Kartashov, Andy" <Andy.Kartas...@mpac.ca>
Subject RE: Trouble with Word Count example
Date Thu, 29 Nov 2012 19:13:52 GMT
Can you try running jar -tvf word_cnt.jar and see if your static nested classes WordCount2$Map.class
and WordCount2$Reduce.class have actually been added to the jar.


From: Sandeep Jangra [mailto:sandeepjangra@gmail.com]
Sent: Thursday, November 29, 2012 1:36 PM
To: user@hadoop.apache.org
Subject: Re: Trouble with Word Count example

Also, I did set the HADOOP_CLASSPATH variable to point to the word_cnt.jar only.

On Thu, Nov 29, 2012 at 10:54 AM, Sandeep Jangra <sandeepjangra@gmail.com<mailto:sandeepjangra@gmail.com>>
Thanks for the quick response Mahesh.

I am using the following command:

sudo -u hdfs hadoop jar word_cnt.jar WordCount2  /tmp/root/input /tmp/root/output15  -libjars=word_cnt.jar
(The input directory exists on the hdfs)

This is how I compiled and packaged it:

javac -classpath /usr/lib/hadoop-0.20-mapreduce/hadoop-core.jar:/usr/lib/hadoop/*  -d word_cnt
jar -cvf word_cnt.jar -C word_cnt/ .

On Thu, Nov 29, 2012 at 10:46 AM, Mahesh Balija <balijamahesh.mca@gmail.com<mailto:balijamahesh.mca@gmail.com>>
Hi Sandeep,

           For me everything seems to be alright.
           Can you tell us how are you running this job?

Calsoft Labs.
On Thu, Nov 29, 2012 at 9:01 PM, Sandeep Jangra <sandeepjangra@gmail.com<mailto:sandeepjangra@gmail.com>>
Hello everyone,

  Like most others I am also running into some problems while running my word count example.
  I tried the various suggestion available on internet, but I guess it;s time to go on email

  Here is the error that I am getting:
  12/11/29 10:20:59 WARN mapred.JobClient: Use GenericOptionsParser for parsing the arguments.
Applications should implement Tool for the same.
12/11/29 10:20:59 WARN mapred.JobClient: No job jar file set.  User classes may not be found.
See JobConf(Class) or JobConf#setJar(String).
12/11/29 10:20:59 INFO input.FileInputFormat: Total input paths to process : 1
12/11/29 10:20:59 INFO util.NativeCodeLoader: Loaded the native-hadoop library
12/11/29 10:20:59 WARN snappy.LoadSnappy: Snappy native library is available
12/11/29 10:20:59 INFO snappy.LoadSnappy: Snappy native library loaded
12/11/29 10:21:00 INFO mapred.JobClient: Running job: job_201210310210_0040
12/11/29 10:21:01 INFO mapred.JobClient:  map 0% reduce 0%
12/11/29 10:21:07 INFO mapred.JobClient: Task Id : attempt_201210310210_0040_m_000000_0, Status
java.lang.RuntimeException: java.lang.ClassNotFoundException: Class WordCount2$Map not found
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:1439)
at org.apache.hadoop.mapreduce.task.JobContextImpl.getMapperClass(JobContextImpl.java:191)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:605)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:325)
at org.apache.hadoop.mapred.Child$4.run(Child.java:270)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:416)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1232)
at org.apache.hadoop.mapred.Child.main(Child.java:264)
Caused by: java.lang.ClassNotFoundException: Class WordCount2$Map not found
at org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:1350)
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:1437)
... 8 more

And here is the source code:

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;

import java.io.IOException;
import java.util.StringTokenizer;

public class WordCount2 extends Configured implements Tool {

    public static class Map extends Mapper<LongWritable, Text, Text, IntWritable> {
        private final static IntWritable one = new IntWritable(1);
        private Text word = new Text();

        protected void map(LongWritable key, Text value, Context context) throws IOException,
InterruptedException {
            String line = value.toString();
            StringTokenizer tokenizer = new StringTokenizer(line);
            while (tokenizer.hasMoreTokens()) {
                context.write(word, one);


    public static class Reduce extends Reducer<Text, IntWritable, Text, IntWritable>

        protected void reduce(Text key, Iterable<IntWritable> values, Context context)
throws IOException, InterruptedException {

            int sum = 0;

            for(IntWritable value : values) {
                sum += value.get();
//                    while (values.hasNext()) {
//                          sum += values.next().get();
//                        }
            context.write(key, new IntWritable(sum));


    public int run(String[] args) throws Exception {
        Configuration conf = getConf();
        for (java.util.Map.Entry<String, String> entry: conf) {
            System.out.printf("%s=%s\n", entry.getKey(), entry.getValue());

        System.out.println("arg[0]= "+args[0] + " args[1]= "+ args[1]);

        Job job = new Job(conf, WordCount2.class.getSimpleName());





        FileInputFormat.setInputPaths(job, new Path(args[0]));
        FileOutputFormat.setOutputPath(job, new Path(args[1]));

        System.exit(job.waitForCompletion(true) ? 0 : 1);

        return 0;

    public static void main(String[] args) throws Exception {
        int exitCode = ToolRunner.run(new WordCount2(), args);

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