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https://issues.apache.org/jira/browse/MRUNIT-156?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13476852#comment-13476852
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Bertrand Dechoux commented on MRUNIT-156:
-----------------------------------------
Use @Override when overriding methods. You will see that you are not redefining
the map method of the Mapper.
And you reducer test is wrong, 1+2 = 3 and not 6 indeed.
And you may have forgotten this in your main
job.setMapOutputKeyClass(Text.class);
job.setMapOutputValueClass(IntWritable.class);
If you want a feedback on you initial problem, you have to provide more
information.
But it is very likely a configuration error from your part.
> 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
> Attachments: WordCount.java, WordCountTest.java
>
>
> 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.
> 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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