Category Archives: I am Learning

java.lang.IncompatibleClassChangeError: Found interface org.apache.hadoop.mapreduce.TaskInputOutputContext, but class was expected

While writing the unit java.lang.IncompatibleClassChangeError: Found interface org.apache.hadoop.mapreduce.TaskInputOutputContext, but class was expected test cases for my
application I was getting the below mentioned exception during the execution of these test cases. Below is the  complete exception trace :

java.lang.IncompatibleClassChangeError: Found interface org.apache.hadoop.mapreduce.TaskInputOutputContext, but class was expected
	at org.apache.hadoop.mrunit.internal.mapreduce.AbstractMockContextWrapper.createCommon(AbstractMockContextWrapper.java:59)
	at org.apache.hadoop.mrunit.internal.mapreduce.MockMapContextWrapper.create(MockMapContextWrapper.java:77)
	at org.apache.hadoop.mrunit.internal.mapreduce.MockMapContextWrapper.(MockMapContextWrapper.java:68)
	at org.apache.hadoop.mrunit.mapreduce.MapDriver.getContextWrapper(MapDriver.java:167)
	at org.apache.hadoop.mrunit.mapreduce.MapDriver.getContext(MapDriver.java:198)
	at com.techidiocy.integratekeys.mapreduce.test.TestIntegrationKeysMapper.init(TestIntegrationKeysMapper.java:37)
	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:606)
	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.RunBefores.evaluate(RunBefores.java:27)
	at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:69)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:48)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:292)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
	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)

Continue reading java.lang.IncompatibleClassChangeError: Found interface org.apache.hadoop.mapreduce.TaskInputOutputContext, but class was expected

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org.datanucleus.store.rdbms.exceptions.MappedDatastoreException: INSERT INTO “TABLE_PARAMS” – Hive with Kite Morphlines

rdbms.exceptions.MappedDatastoreException: INSERT INTO “TABLE_PARAMS”

If you had read my previous post (Anatomy of a configuration file) where i hive_logo
described the flow of the application
on which I was working . In the last
command of my morphline I was
creating the hive table using the avro
schema which was created in the previous command.
As per the design of my application I
decided that i will store my avro schema
file in the local file system instead of saving it on HDFS. Everything was working fine as expected , but things started breaking when my avro schema file contains more than 4000 characters. Below is the complete exception which I got while Hive table creation :

org.datanucleus.store.rdbms.exceptions.MappedDatastoreException: INSERT INTO “TABLE_PARAMS” 
Continue reading org.datanucleus.store.rdbms.exceptions.MappedDatastoreException: INSERT INTO “TABLE_PARAMS” – Hive with Kite Morphlines

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java.io.IOException: can not read class parquet.format.PageHeader: null – Hive

While evaluating the Cloudera Kite Morphlines , java.io.IOException: can not read class parquet.format.PageHeader:
I came across this exception while reading the
data from the table.

java.io.IOException: can not read class
parquet.format.PageHeader: null
.

Before going ahead let me give you the background what I am trying to do here.
I am building an application where external client will upload input XML files and there corresponding XSDs ,once these files are uploaded a job will run that will unmarshall these XML files into Java objects , later on these these java objects will be passed to Drools Framework where validation and minor transformations will be performed on this data. During this Continue reading java.io.IOException: can not read class parquet.format.PageHeader: null – Hive

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Single Field Indexes MongoDB Java Example

Indexing MongoDB Java Example

Indexing in MongoDB works in theIndexing in MongoDB same way as it is used to work in relational databases.It helps in the fast retrieval of documents available in MongDB . Having an index over a collection ensures that least numbers of documents are scanned to find the documents matching search criteria. Hence having an understanding of indexes is very important for the efficient performance of your application. In this post we will cover: Continue reading Single Field Indexes MongoDB Java Example

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MongoException multi update only works with $ operators

It is quite possible for the first MongoDB Official Logotime when you are working with Multiple documents update in MongoDB you might see this exception.
Exception in thread “main” com.mongodb.MongoException: multi update only works with $ operators Continue reading MongoException multi update only works with $ operators

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Update Multiple Documents MongoDB Java Example

This post will talk about Update Multiple Documents MongoDB Java Example.
In the last few examples MongoDB Official Logowe have seen that, we are using the default version of update() method , where it takes 2 arguments i.e. search criteria object and modified object. Whenever this version of update() method is executed it updates only Continue reading Update Multiple Documents MongoDB Java Example

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Upsert MongoDB Java Example

This post will talk about upsert mongodb java example.
Consider a scenario where we have to MongoDB Official Logo
write the logic such that – we will
search for a record in the database
and if it is available in database we
will update it else we will insert a
new record with same information.
Conventional solution for this type of problem is first you will try to find the record in MongoDB either using findOne() or find() , and on Continue reading Upsert MongoDB Java Example

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Can’t serialize class – MongoDB Illegal Argument Exception

While working on the array modifiers example MongoDb
, I was trying to use the $sort
modifier with $each and $push modifier
.In that example I added
an array of books to my original
document and was trying to sort it on the basis of one of the fields.As soon as I executed that method,i got our infamous IllegalArgumentException : Exception in thread “main” java.lang.IllegalArgumentException: can’t serialize class com.lotusmedia.mongo.models.Book (Can’t serialize class – MongoDB). Continue reading Can’t serialize class – MongoDB Illegal Argument Exception

Array Modifiers Update MongoDB Java Example

This post is in continuation of our Update MongoDB Java Example series.

In the previous post we have Logical Querying MongoDB Java Exampleseen some of the Atomic update modifiers provided by MongoDB with the help of a Java example ,that can be used to
update and add new key to a
document. Now we will move one step ahead and will look into the Array modifiers available in MongoDB. Below are the following Array Modifiers that we are going to cover in this post.

  • $push
  • $each
  • $slice

Continue reading Array Modifiers Update MongoDB Java Example