posa Wu created MRUNIT-156:
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Summary: java.lang.IncompatibleClassChangeError: Found class
org.apache.hadoop.mapreduce.TaskInputOutputContext, but interface was expected
Key: MRUNIT-156
URL: https://issues.apache.org/jira/browse/MRUNIT-156
Project: MRUnit
Issue Type: Bug
Affects Versions: 0.9.0
Environment: fedora,eclipse
Reporter: posa Wu
Priority: Minor
This is the my first time to use MRUnit，the followed program is the WordCount，
I can not figure out why it throws ：java.lang.IncompatibleClassChangeError:
Found class org.apache.hadoop.mapreduce.TaskInputOutputContext, but interface
was expected.
I have already checked all similar issues but can't fixed.
Thanks in advance.
*********************************************************************************************************************
package tmp;
import java.io.IOException;
import java.util.StringTokenizer;
import org.apache.hadoop.conf.Configuration;
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.output.FileOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;
public class WordCount{
public static class TokenizerMapper
extends Mapper<LongWritable, Text, Text, IntWritable>
{
private final static IntWritable one = new IntWritable(1);
private Text word = new Text();
public void map(Object key, Text value, Context context)
throws IOException, InterruptedException{
StringTokenizer itr = new
StringTokenizer(value.toString());
while(itr.hasMoreTokens()){
word.set(itr.nextToken());
context.write(word, one);
}
}
}
public static class IntSumReducer
extends Reducer<Text, IntWritable, Text, IntWritable>
{
private IntWritable result = new IntWritable();
public void reduce(Text key, Iterable<IntWritable> values,
Context context)
throws IOException, InterruptedException{
int sum = 0;
for(IntWritable val: values){
sum += val.get();
}
result.set(sum);
context.write(key, result);
}
}
public static void main(String args[]) throws IOException,
ClassNotFoundException, InterruptedException{
Configuration conf = new Configuration();
String[] otherArgs = new GenericOptionsParser(conf,
args).getRemainingArgs();
if(otherArgs.length != 2){
System.err.println("Usage: wordcount <int> <out>");
System.exit(2);
}
Job job = new Job(conf, "word count");
job.setJarByClass(WordCount.class);
job.setMapperClass(TokenizerMapper.class);
job.setCombinerClass(IntSumReducer.class);
job.setReducerClass(IntSumReducer.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
FileInputFormat.addInputPath(job, new Path(otherArgs[0]));
FileOutputFormat.setOutputPath(job, new Path(otherArgs[1]));
System.exit(job.waitForCompletion(true)?0:1);
}
}
package test;
import java.util.ArrayList;
import java.util.List;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mrunit.mapreduce.MapDriver;
import org.apache.hadoop.mrunit.mapreduce.MapReduceDriver;
import org.apache.hadoop.mrunit.mapreduce.ReduceDriver;
import org.junit.Before;
import org.junit.Test;
import tmp.WordCount.IntSumReducer;
import tmp.WordCount.TokenizerMapper;
public class WordCountTest {
MapDriver<LongWritable, Text, Text, IntWritable> mapDriver;
ReduceDriver<Text, IntWritable, Text, IntWritable> reduceDriver;
MapReduceDriver<LongWritable, Text, Text, IntWritable, Text,
IntWritable> mapReduceDriver;
@Before
public void setUp(){
TokenizerMapper mapper = new TokenizerMapper();
IntSumReducer reducer = new IntSumReducer();
mapDriver = MapDriver.newMapDriver(mapper);
reduceDriver = ReduceDriver.newReduceDriver(reducer);
mapReduceDriver = MapReduceDriver.newMapReduceDriver(mapper,
reducer);
}
@Test
public void testMapper(){
mapDriver.withInput(new LongWritable(3243), new Text("hello"));
mapDriver.withOutput(new Text("hello"), new IntWritable(1));
mapDriver.runTest();
}
@Test
public void testReducer(){
List<IntWritable> values = new ArrayList<IntWritable>();
values.add(new IntWritable(1));
values.add(new IntWritable(2));
reduceDriver.withInput(new Text("posa"), values);
reduceDriver.withOutput(new Text("posa"), new IntWritable(6));
reduceDriver.runTest();
}
}
java.lang.IncompatibleClassChangeError: Found class
org.apache.hadoop.mapreduce.TaskInputOutputContext, but interface was expected
at
org.apache.hadoop.mrunit.mapreduce.mock.MockContextWrapper.createCommon(MockContextWrapper.java:53)
at
org.apache.hadoop.mrunit.mapreduce.mock.MockMapContextWrapper.create(MockMapContextWrapper.java:70)
at
org.apache.hadoop.mrunit.mapreduce.mock.MockMapContextWrapper.<init>(MockMapContextWrapper.java:62)
at org.apache.hadoop.mrunit.mapreduce.MapDriver.run(MapDriver.java:217)
at
org.apache.hadoop.mrunit.MapDriverBase.runTest(MapDriverBase.java:150)
at org.apache.hadoop.mrunit.TestDriver.runTest(TestDriver.java:137)
at test.WordCountTest.testMapper(WordCountTest.java:41)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at
org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
at
org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at
org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
at
org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
at
org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at
org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
at
org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:73)
at
org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:46)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:180)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:41)
at org.junit.runners.ParentRunner$1.evaluate(ParentRunner.java:173)
at
org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at
org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
at org.junit.runners.ParentRunner.run(ParentRunner.java:220)
at
org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49)
at
org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
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