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From "laozhao0@sina.cn" <laozh...@sina.cn>
Subject Re: Re: Hadoop NoClassDefFoundError
Date Wed, 16 Apr 2014 08:23:04 GMT






I used  the belowest code to compile and package the source file . Any wrong ?



laozhao0@sina.cn
 From: Rahul SinghDate: 2014-04-16 16:44To: userSubject: Re: Re: Hadoop NoClassDefFoundErrorWhen
i unzip my jar.. i get the class files inside the package hirarchy while in your case all
files are lying outside? are you  sure your jar was properly created?



On Wed, Apr 16, 2014 at 1:21 PM, laozhao0@sina.cn <laozhao0@sina.cn> wrote:


This is the result .
/home/laozhao0 $ unzip -l myjob.jar
Archive: /home/laozhao0/myjob.jar
Length Date Time Name
--------- ---------- ----- ----

0 04-15-2014 14:54 META-INF/
71 04-15-2014 14:54 META-INF/MANIFEST.MF
1300 04-15-2014 14:54 MyJob$MapClass.class

1628 04-15-2014 14:54 MyJob$Reduce.class
2160 04-15-2014 14:54 MyJob.class
--------- -------

5159 5 files



laozhao0@sina.cn
 
From: Stanley ShiDate: 2014-04-16 10:25To: user@hadoop.apache.org
Subject: Re: Re: Hadoop NoClassDefFoundErrorcan do you an "unzip -l myjob.jar" to see if
your jar file has the correct hierarchy?

Regards,Stanley Shi,




On Tue, Apr 15, 2014 at 6:53 PM, laozhao0@sina.cn <laozhao0@sina.cn> wrote:



Thank you for your advice . When i user your command , i get the below error info .

$ hadoop jar myjob.jar myjob.MyJob input output

Exception in thread "main" java.lang.ClassNotFoundException: myjob.MyJob
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)


at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)


at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
at java.lang.Class.forName0(Native Method)


at java.lang.Class.forName(Class.java:264)
at org.apache.hadoop.util.RunJar.main(RunJar.java:149)




 

From: Azuryy YuDate: 2014-04-15 16:14To: user@hadoop.apache.org

Subject: Re: Hadoop NoClassDefFoundErrorPlease use: hadoop jar myjob.jar myjob.MyJob input
output




On Tue, Apr 15, 2014 at 3:06 PM, laozhao0@sina.cn <laozhao0@sina.cn> wrote:


Hello EveryOne:    I am new to hadoop,and i am reading Hadoop in action.When i tried to
run a demo from this book,I got a problem and could not find answer from the net. Can you
help me on this ?


below is the error info :




 $ hadoop jar myjob.jar MyJob input output

Exception in thread "main" java.lang.NoClassDefFoundError: MyJob (wrong name: myjob/MyJob)
at java.lang.ClassLoader.defineClass1(Native Method)


at java.lang.ClassLoader.defineClass(ClassLoader.java:791)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)


at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
at java.net.URLClassLoader.access$100(URLClassLoader.java:71)


at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)at java.security.AccessController.doPrivileged(Native
Method)


at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)


at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:264)
at org.apache.hadoop.util.RunJar.main(RunJar.java:149)



and this is the command that i compile the .java , I compiled in Win7 and ran on ubuntu .



below is MyJob.java
package myjob;



import java.io.IOException;

import java.util.Iterator;



import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.conf.Configured;

import org.apache.hadoop.fs.Path;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapred.FileInputFormat;

import org.apache.hadoop.mapred.FileOutputFormat;

import org.apache.hadoop.mapred.JobClient;

import org.apache.hadoop.mapred.JobConf;

import org.apache.hadoop.mapred.KeyValueTextInputFormat;

import org.apache.hadoop.mapred.MapReduceBase;

import org.apache.hadoop.mapred.Mapper;

import org.apache.hadoop.mapred.OutputCollector;

import org.apache.hadoop.mapred.Reducer;

import org.apache.hadoop.mapred.Reporter;

import org.apache.hadoop.mapred.TextOutputFormat;

import org.apache.hadoop.util.Tool;

import org.apache.hadoop.util.ToolRunner;


public class MyJob extends Configured implements Tool{



	@Override

	public int run(String[] args) throws Exception {

		Configuration conf = getConf();

		JobConf job = new JobConf(conf,MyJob.class);

		Path in = new Path(args[0]);

		Path out = new Path(args[1]);

		FileInputFormat.setInputPaths(job, in);

		FileOutputFormat.setOutputPath(job, out);

		job.setJobName("MyJob");

		job.setJarByClass(MyJob.class);

		job.setMapperClass(MapClass.class);

		job.setReducerClass(Reduce.class);

		

		job.setInputFormat(KeyValueTextInputFormat.class);

		job.setOutputFormat(TextOutputFormat.class);

		job.setOutputKeyClass(Text.class);

		job.setOutputValueClass(Text.class);

		job.set("key.value.separator.in.input.line",",");

		JobClient.runJob(job);

		return 0;

	}

	

	public static class MapClass extends MapReduceBase implements Mapper<Text,Text,Text,Text>{



		@Override

		public void map(Text key, Text value, OutputCollector<Text, Text> output,

				Reporter reporter) throws IOException {

			output.collect(value, key);

		}

	}

	

	public static class Reduce extends MapReduceBase implements Reducer<Text,Text,Text,Text>{



		@Override

		public void reduce(Text key, Iterator<Text> values,

				OutputCollector<Text, Text> output, Reporter reporter)

				throws IOException {

			String csv = "";

			while(values.hasNext()){

				if(csv.length() > 0)

					csv += ",";

				csv += values.next().toString();

			}

		}

	}



	public static void main(String[] args) throws Exception {

		int res = ToolRunner.run(new Configuration(), new MyJob(), args);

		System.exit(res);

	}

} 

Thank you for your kindly help !









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