Introduction To ZooKeeper


Work for ZooKeeper

Introduction To ZooKeeper

ZooKeeper is a coordination service. that built for the reliable sent out the system. This open up source server developed and managed to be accessible by all. It makes the cluster coordination to be scalable and install faster. It works on the cluster of machines. This service offers a predefined operation. The best appropriate application is to read dominating workloads. This work made with the goal of maintaining the small quantities of data or Meta data. Clients have the shared configuration system and read from and write to the nodes Work for ZooKeeper.

  Work for ZooKeeper 

Apache Software Basis has initiated this software project of ZooKeeper. The purpose of this project is open source sent out confirmation service. The naming registry and synchronization services for the top distributed systems. it started as a little and sub job of Hadoop, it turned to be the top-level task, developed its own.

ZooKeeper provides high availableness through its redundant services. so, the client can approach the next or another ZooKeeper expert, when the first one does not answer Hadoop training in Hyderabad.

How does ZooKeeper work

Zookeeper works through an ensemble of servers. The changes written by the clients to the ensemble. The changes of the data would be completely based on the order of received to process. Here the ensemble selects the leader. In the event, any circumstances of the failure of the system, the leader would be re elected.

The changes by the client created successfully. when, it reaches a quorum, which is at least half ensemble. The client disconnected by the server in the event. it cannot contact quorum within the stipulated given time. The entire cluster would function when one-half of the machines are up. In the event a server does not work, after it re starts and resumes its function, it would re-sync with the outfit Work for ZooKeeper.

Issues for the Zookeeper

the sent out system problems experienced are inconsistency, contest condition, and lifeless hair. The inconsistency caused by the construction inconsistencies found in across the cluster. The unexpected behavior due to timings of various events. the competition condition becomes a significant concern for the distributed system. Dead locks will be the issues which result in contention for the resources Hadoop training institutes in Hyderabad.

When it comes to the ZooKeeper it resolves many of the issues and part of the type used in the situations.
  • Naming service
  • Synchronization
  •  Leader election
  •  Message Queue
  •  Configuration Management
  • Notification System
 Use for Zookeeper

ZooKeeper nodes generally use the hierarchical name space to store the data.  the standard data file system but is bound for low data volumes and not for the high amounts of the info. Within the hierarchy, the path elements segregated by / or slash. Here route identifies every node present in the name space.

 The zookeeper put in place and utilized by the companies like Yahoo!, Rackspace and eBay. It is even utilized by the wide open source business search systems such as Solr Work for ZooKeeper.

  Work for ZooKeeper 

  We provide Work for ZooKeeper in real time training. We offer classroom and spark installation of Hadoop training in Hyderabad.

Data Is Used Around the World  in Weird Ways

Data use Types of Weird ways


Data Is Used Around the World in Weird Ways

Big Data is business insiders use to transformational change in examination and supervision. It signifies the cutting and marvelous informational indexes to find. The shocking bits of knowledge and information into the way the earth works. It’s a hot field as of this moment in view of twin upsets heading forward in the way of measuring. PC information accessible development of calculations and investigation used to review Data use Types of Weird ways.

 Data use Types of Weird ways 

Where PC experts limited to simple gigabytes or terabytes of data. they’re currently analyzing petabytes and even Exabyte’s of data. They don’t need to know the mathematics to realize gigantic total. With such great acceptance of this principle, there are many specialists in the IT field. They get trained in Big Data Knowledge through various professional training institutes Hadoop Training in Hyderabad.

Here four weird ways data used these days

1. Big Data Billboards

 The marketing company, Option is utilizing enormous information to characterize and legitimize. its estimating model for space on announcements, seating and the edges of transports. The available air multi media valuing assessed “per impression” in the light. the gauge of the range of eyes would see the advertisement in the confirmed day. they’re utilizing advanced Gps navigation, eye-following programming. The inspection of movement cases to smart considered. which marketing promotions saw the most – and so be the best Hadoop Training institutes in Hyderabad.

2. Big Data and Foraging

The searching maps and road tree databases to provide an instinctive guide to reveal. where in fact the apple and cherry trees in your neighborhood may drop the natural product. The site’s indicated aim is to remind urbanites. that farming and regular sustenances do are present in the location. it might very well have to get to a niche site to find it Data use Types of Weird ways.

3. Huge Data on the Slopes

Ski resorts are in spite of getting into the info diversion. RFID labels embedded into seat tickets extortion and endure times at the lifts. it helps ski resorts comprehend activity designs. which elevates and operates are most well-known times of the day. The help keeps track of the advancements of a person skier managed to finish up lost. the information population, presenting sites and applications. that show day’s details volume of works slalomed quantity of vertical ft crossed. which are talk web-based networking multimedia or content with family and companions Hadoop Training in Hyderabad.

4. Enormous Data Weather Forecasting

Applications have quite utilized information from telephones to populate activity maps. the credit card application called WeatherSignal. The advantage of detectors with Android telephones to crowdsource ongoing local climate information. The telephones include a gauge, hygrometer, surrounding thermometer and light meter. The information important to climate gauging and bolstered into prescient models Hadoop Training institutes in Hyderabad.

 Data use Types of Weird ways 

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Big Data Analytics Using Hadoop

Use of Big Data Analytics in Hadoop

Big Data Analytics Using Hadoop

The large heap of data made every day is supplying rise to the Big Data. The effective analysis of this data is getting the necessity for each organization Use of Big Data Analytics in Hadoop.

 Use of Big Data Analytics in Hadoop

Hadoop servers for Big Data Analytics and facilitates the organizations manage the info Hadoop training in Hyderabad.

Big Data Analytics

The procedure of gathering, regulating and a large amount of data Big Data Analytics. This process, different habits, and other helpful information derived. that helps the companies in identifying the factors that boost up the gains Use of Big Data Analytics in Hadoop.

What is it required?

 The analyzing the large heap of data technique turns very helpful. it creates use of the particular software tools. The application helps in the predictive evaluation, data optimization, and content material mining details. Hence, it requires some high-performance analytics Hadoop training in Hyderabad.

The processes contain functions included and the analytics that assurance high-performance. When a venture uses the various tools and the software. it gets a concept about making the apt decisions for the firms. The relevant data analyzed and studied to know the market tendencies.

What Challenges Does it Face?

Many organizations complete various challenges. the reason behind is a large number of data saved in a variety of formats, set up and unstructured forms. the resources differ, as the info compiled from different sections of the organization Hadoop training in Hyderabad.

Thus, breaking down the data stored in several places or different systems. It is one of the challenging tasks. Another obstacle typed the unstructured data in the way. that it becomes as available as the ease of access to set up data.

How is it used in Recent Days?

The wearing down of data into small chunks helps the business enterprise to a high scope. It helps in the transformation and achieving expansion. The research also helps the research workers to analyze the human patterns. the pattern of replies toward particular activity, decoding countless individual DNA combinations. predict the terrorists plan for any assault by studying the prior trends. studying different genes that are in charge of specific diseases Use of Big Data Analytics in Hadoop.

Benefits of Big Data Analytics:

 three classifications under benefits

COST Savings:
The program helps the business enterprise in keeping the massive amount of data. It eliminating spending the total amount on the traditional database. The data usually stored in the clusters. The transferred to the original database for further analysis required Use of Big Data Analytics in Hadoop.

Competitive edge:
The analytics help the organizations to access before unavailable data. that data was difficult in being able to access. this increase in data access help to understand the product and work. like planning the business enterprise strategies hence, facing the competitive problems Hadoop training in Hyderabad.

New business offers:
It helps in discovering the trending business opportunities. Many corporations use the gathered for the customer trends and new product amounts.

 Use of Big Data Analytics in Hadoop

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Hadoop Training and Certification for Professionals

Use for Hadoop Training

Hadoop Training and Certification for Professionals

Hadoop skills are the clamor for an indisputable reality. The Allied GENERAL MARKET TRENDS says the Global Hadoop Market may reach $84.6 Billion by 2021Use for Hadoop Training.

 Use for Hadoop Training

Big Data technology won’t refrain from but Hadoop is a skill in the present day situation. the hub of Big Data alternatives for many corporations. The new solutions like Spark have changed around Hadoop training in Hyderabad.

The scope of getting trained under Hadoop?

  • Hadoop in HDFS, MapReduce, HBase, Zookeeper, Yarn, Oozie, Flume, and Sqoop using real-time. It uses conditions on Retail, Aviation, Travel and leisure, Finance domain.
  • This program is stepping rock to Big Data voyage. the possibility to work on a large data Analytics task choosing the data-set of the decision.
  • Detailed knowledge of Big Data analytics. The market for Big Data analytics keeps growing around the world. which strong growth pattern translates into a great chance of all the IT Experts
  • Hadoop in HDFS, MapReduce, HBase, Zookeeper, Yarn, Oozie, Flume, and Sqoop using real-time. use conditions on Retail, Aviation, Travel and leisure, Finance domain Hadoop training institutes in Hyderabad
  • Mastering Hadoop administration activities cluster managing, monitoring, administration, and troubleshooting. configuring ETL tools like Pentaho/Talend to use MapReduce are a thing into the future.
  • Big Data is fastest growing. The promising technology for managing large quantities of data for doing data analytics. This Big Data Hadoop Qualification Training Course help. It running in the most demanding professional skills.
  • Hadoop practitioners are among the best paid IT professionals salaries. the marketplace demand for them is growing.
  • Gives an advantage over different experts in the same field. The conditions of pay package and Confirms mindful of the most recent elements of Hadoop.
  • Hadoop training from an established education Academy helps Hadoop Certification Training course. which in turn helps to build an aspiring career in cutting edge technologies Hadoop training in Hyderabad.


 It Recognition demonstrates functionality as a Hadoop Builder. The Hadoop qualification program is a mixture of Hadoop designer. Hadoop Administrator, Hadoop tests, and analytics. It industry job requirements to provide learning on big data and Hadoop Modules. Organizations are battling to hire Hadoop builders. The mercantile endeavors are obtaining Hadoop need affirmation. that the individuals work with equipped. when planning for treatment of their petabytes of information develop Hadoop tools.

The recognition is a proof of this ability. these said the affirmation, making trustworthy and a mindful individual because of their information Use for Hadoop Training.

People who should consider a Hadoop Recognition course
  • Programming Builders and Architects
  • Experienced working experts and BI /ETL/DW professionals
  • Big Data Hadoop Creators eager to learn other verticals. like Examining, Analytics, Administration
  • Coders and Architects
  • Mature IT and Examining Professionals
  • Mainframe professionals
  • Graduates and Post Graduates

Thus, to stand out in the entrenched technology of Apache Hadoop. it recommended any particular at least learn Java basic principles Hadoop training in Hyderabad.

 Use for Hadoop Training

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Career Opportunities Hadoop Training

Opportunities for Hadoop Training

Career Opportunities Hadoop Training

It is an extending field. where technology helps to keep changing and data will keep mounting Opportunities for Hadoop Training.

Opportunities for Hadoop Training

Data soon becomes Big Data and it gets complex to not store, but manage this voluminous chink of piling data Hadoop training in Hyderabad.

What is Big Data Hadoop?

Big data associated with Hadoop these days. Hadoop open up source tool. that used to manage amounts of data and examine it. so the knowledge gained applied to take smart and determined business decisions. Hadoop reveals a simple and convenient way to control disparate data. The sensible of computer managers gain useful insights for better productivity & business growth. The ultimate way to garner huge benefits from this technology. The get a Hadoop Certification and increase the great things Hadoop in the organization opportunities for Hadoop Training.

Job Opportunities after Hadoop Training

A Hadoop Course from a respected and authorized training partner. Must, to begin with on this website. Hadoop training and Hadoop Certification the position of any Hadoop administrator. Hadoop Creator, Hadoop Architect or Hadoop analyst depending after the Hadoop. The recognition took by the individual and his/her expertise in their individual field Hadoop training in Hyderabad.

1. Hadoop administrators are system administrators. Who knowledge of repository management, Java, and Linux to learn in-depth about MapReduce. the ground breaking programming algorithm for data control.

2. Hadoop developers SQL and Main Java to get started in creating Big Data Hadoop solutions.

3. Hadoop Architects become expert in Java, MapReduce, HBase, Pig, and Hive.

4. Hadoop Experts must have got the understanding of data examination software solutions. such as R, SAS, SPSS.

Industrial Applications of Hadoop

1. Retail industry: Needs Hadoop for connecting to customers in a better way. The forecasting their buying habits and preferences.

2. Banking & Financing: Implements Hadoop to find solutions to reduce our workloads and efficiency.

3. Manufacturing: Needs to take care of data using a competent tool. that can store data from various resources and streamline different operations. the source to equipment control procedures.

4. Healthcare: Involves huge amount of data about patient records. scientific and financial data and health background to name a few.

5. Sports: Sports Industry utilizes Big Data for game evaluation. player auctions, broadcasting past styles, and health management of players Hadoop training in Hyderabad.

Opportunities for Hadoop Training

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Big Data and Its Importance for an Enterprise

Hadoop Training Institutes in Hyderabad

Big Data and Its Importance for an Enterprise and Hadoop Training in Hyderabad

In IT wording, Big Data Hadoop training in Hyderabad characterized an accumulation of informational collections. Which are mind boggling and expansive that information can’t effortlessly caught, put away, sought, shared, envisioned utilizing accessible instruments. Different zones, where Big Data ceaselessly shows up incorporate different fields of research including the human genome and nature. The constraints brought about by Big Data essentially influence the business informatics, back business sectors and Internet indexed lists

The significance of such huge datasets can’t overemphasized extraordinarily to organizations working in times instability. Where the quick preparing of market information to bolster basic leadership might be contrast amongst survival and elimination. I as of late ran over an article on Big Data Hadoop training institutes in Hyderabad and suggestion for businesses in Ireland.  As indicated by the creator, one reason for Ireland’s dependence on Big Data is developing of Euro zone emergency. Be that as it may, the impacts of the twofold plunge retreat in Europe would influence advertises everywhere throughout the world.

In world, where advanced cells surpass PCs, Big Data Analytics relied upon. Those are to be following huge with US, European and different Asian organizations putting fundamentally in field. The present information hotpots for Big Data Hadoop training in Hyderabad  corporates however not restricted to purchaser from retailers. Big Data created through cooperation of various components, progresses in examination of substantial datasets  required to bring about presentation systems. Ffit for taking care of ever increasing number of factors utilizing accessible figuring assets.

As of late publicized Commercial employments of Big Data Hadoop Training institutes in Hyderabad 

The wellspring information was data gathered by target from its clients amid past visits to their outlets. Every purchaser allocated ID number in Target’s database and their buys are followed. This data was prepared and utilized by Target with specific end goal to anticipate client purchasing examples and configuration focused on promoting efforts.

Extra wellsprings of these datasets for use by business knowledge arrangements incorporate data accessible on open discussions. Person to person communication locales, for example, LinkedIn, Twitter and also the advanced shadows left by our visit to sites. Aside from business utilize, the ability to gather, characterize and break down such substantial information amounts would likewise be essential for Healthcare business by helping the recognizable proof and investigation of medication connections, individual restorative and also different social and financial elements which influence result of medicines. The investigation of Big Data learn Hadoop alludes to another universe of information science, which Cisco evaluations contained around 10 billion web empowered gadgets.

The Road Ahead for Market Growth and Hadoop Training Hyderabad

In spite of fact that industry investigators and specialists concur that Big Data Hadoop training Hyderabad.  Analytics is the following upheaval the field of information examination, as subject of much open deliberation. Current proposals to advance development of field include:

  • Establishment of uncommon courses to grant the important aptitudes
  • Inclusion of these logical procedures as a paper in driving Applied Sciences courses
  • Government-drove activities with industry organization to produce mindfulness among open

These are just few of the recommendations, which would help this rising investigation showcase form into the fate of all information examination over various enterprises.

Hadoop Training in Hyderabad

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World’s Buzzing Word Hadoop


Hadoop training in Hyderabad

World’s Buzzing Word Hadoop Training Institutes in Hyderabad

The word cloud has turn out to be the humming word to the today’s emerging technologies. Which brought in corporate international. The maximum acquainted era used for massive statistics is Hadoop training in Hyderabad.  Getting to know of Hadoop training makes you earn extra along with very good career boom. Hadoop free Java based programming utility tool. This supports the handing out of big amounts of facts units by using the usage of simple packages.

Simultaneously in the course of many servers. It belongs to Apache undertaking added with aid of Apache software program foundation. It turned into utilized by many net based totally organizations like Yahoo, Google, eBay, LinkedIn, fb and IBM. While as compared to different technology, the principle advantage of Hadoop packages is fantastically flexible as well as robust and efficient.

Core components of Hadoop Training in Hyderabad

The Hadoop architecture changed into made up of elements. One is HDFS (Hadoop dispensed file machine) at the same time as the alternative is learn Hadoop MapReduce.  Hadoop dispensed record gadget (HDFS) is digital file system. When you flow file on HDFS so that will be split into lots of small documents which had been replicated and saved on extraordinary servers for fault tolerance constraints.

Hadoop MapReduce is  Java-based gadget device used to paintings with the records itself. MapReduce plays major role while compared to HDFS.As this, device used for information processing and makes the human beings get extra interest while they may be operating.

The primary function of MapReduce is to run series of jobs based totally on Java software that tactics the facts and pulls out the wished facts. MapReduce is quite complicated but in place of query and gives variety of strength and versatility.

In standard, Hadoop isn’t always a database. Hadoop training in Hyderabad is extra records warehousing machine without queries concerned. So, it makes use of system like MapReduce to method the statistics.

Call for Hadoop Training Hyderabad

Because the days go on, day by day billions photos, motion pictures, and lots many stuff dumped on net so many websites like fb, YouTube, and so on. To manage this massive amount of data, Hadoop training technology has emerged inside the marketplace with an inexpensive charge.

What makes human beings pass for Hadoop?

All and sundry wants to have growth in their profession at the side of hikes related to their package deal. At gift, the corporate global is displaying extra interest toward the cloud-based totally technology to get greater performance. As most of the big corporations are hiring the folks who are agile with the modern-day technologies. Overall global is tending to move for Hadoop training in Hyderabad to get a higher career with a very good bundle.

Hadoop Training in Hyderabad

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Introduction to Big Data Hadoop & Its flavours

Hadoop Training In Hyderabad
Introduction to Big Data Hadoop & Its flavours

Hadoop training is an open source framework that allows to store and process big data in distributed environment across clusters of computers using simple programming models. It is designed to scale up from single servers to thousands of machines, each offering local computation and  storage. This provides quick introduction to Big Data, MapReduce algorithm, and Hadoop Distributed File System. This has been prepared for professionals to learn the basics of  Big Data Analytics using Hadoop Framework and become a learn Hadoop Developer.Software  Professionals,Analytics Professionals, and ETL developers.

What is Big Data? Hadoop Training in Hyderabad

Big data means really big data, its collection of large data sets that cannot be processed using traditional computing techniques. Big data  not data, otherwise it has become a complete subject, which involves various tools, technqiues and frameworks.

what is Hadoop……? Hadoop Training

Hadoop is an open source, Java based programming framework that supports the processing and  storage of extremely large data sets in a distributed computing environment. Its part of  the Apache project sponsored by the Apache Software Foundation.

Flavoures of Hadoop Training Institutes In Hyderabad

We have four types of flavours in hadoop those are follwing,

1. Hadoop Common
2. Hadoop YARN
3. Hadoop Distributed File System
4. Hadoop Map Reduce

These are 4 types of hadoop……and Explain each flavour…

1.Hadoop common:

These Java libraries and utilities required by other Hadoop modules. These libraries  provides filesystem and OS level abstractions and contains the necessary Java files and  scripts required to start Hadoop.

Use:  contains libraries and utilities needed by other Hadoop modules

2.Hadoop YARN:

Apache Hadoop YARN means Yet Another Resource Negotiator is a cluster management technology.  YARN is one of the key features in the second generation Hadoop 2 version of the Apache  Software Foundation’s open source distributed processing framework


The most commonly spun animal fiber wool harvested from sheep. For hand knitting and  hobby knitting, thick, wool and acrylic yarns are frequently used. Other animal fibers  used include alpaca, angora, mohair, llama, cashmere, and silk.

3.Hadoop Distributed File System:

The Hadoop Distributed File System is a distributed file system designed to run on commodity  hardware


learn Hadoop Distributed File System is designed to store very large data sets reliably, and  to stream those data sets at high bandwidth to user applications. In a large cluster,  thousands of servers both host directly attached storage and execute user application tasks
4.Hadoop MapReduce:

Hadoop Map Reduce is a software framework for easily writing applications which process  amounts of data in parallel on large clusters of commodity hardware in a reliable,  fault tolerant manner.


Hadoop Map Reduce. Map Reduce is a framework using which we can write applications to  process huge amounts of data, in parallel, on large clusters of commodity hardware in a reliable manner.
These are four flavours of BigData Hadoop training in hyderabad.………..

Hadoop Training In Hyderabad:

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Hive Overview | Best Hadoop Training Institutes in Hyderabad

Best Hadoop Training Institutes in Hyderabad


Hive Overview


Hive on top of Hadoop as its data warehouse framework for querying and analysis of data stored in HDFS. A hive is an open-source software. That lets programmers analyze large data sets on Hadoop. The performing operations like data encapsulation, ad-hoc queries, and analysis datasets

The hive’s design reflects use as a system for managing and querying structured data. Structured data in general, Map Reduce doesn’t have optimization and usability features. Hive’s SQL- language separates from the complexity of Map-Reduce programming. It re-uses concepts from the relational database world. Such as tables, rows, columns, and schema, too easy learn

Hive Architecture

There are 3 major components in Hive as shown in the architecture diagram. They are hive clients and services stored in Meta Store. Under hive client, we can have different ways to connect to HIVE SERVER in hive services.

These are Thrift client, ODBC driver, and JDBC driver. It provides an easy environment to execute the hive commands from programming languages. Thrift client bindings for Hive are available for C++, Java, PHP scripts, python scripts and Ruby. JDBC and ODBC drivers for communication between client and servers for compatible options.


HIVESERVER is an API. That allows the clients to execute the queries on data warehouse and get the desired results. The services driver, compiler, and execution engine interact with each other.

2.The client submit

The client submits the query via a GUI. The driver receives the queries in the first instance from GUI. It will define session handlers, which will fetch required APIs. Different interfaces like JDBC or ODBC. The compiler creates the plan for the job to execute. The compiler, in turn, is in contact with matter and it gets metadata from Meta Store.


3.Execution Engine

Execution Engine (EE) is the key component. To execute a query by communicating with Job Tracker, Name Node, and Data nodes. As discussed earlier, by running hive query at the backend, it will generate a series of MR Jobs. The execution engine plays like a bridge between hive and Hadoop to process the query.

At the end, EE is going to desired results from Data Nodes. EE will be having bi-directional communication with Metastore. In the hive, the side is a framework to serialize and de-serialize input and output data from HDFS to local.

Metastore used for collection of all the metadata. It’s having backup services to backup Meta store info. The service runs on the JVM as the services of hive running on. The structural information of tables, columns, information stored in this.


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MapReduce Word Count | Best Hadoop Training in Hyderabad



Best Hadoop Training in Hyderabad


MapReduce Word Count



In Hadoop, MapReduce is a computation large manipulation jobs into individual tasks. They execute in parallel cross a cluster of servers. The results of tasks join together to final results

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It consists of two types

1. Map Function


It is a set of data and converts into another set of data. Where individual elements of Key and Value pair into tuples.


2. Reduce Function


the output from Map an input and combines those data tuples into a smaller set of tuples.


Work Flow of Program


 Workflow of MapReduce consists of 5 steps


  1. Splitting

 The splitting parameter can be anything, e.g. splitting by space, comma, semicolon, or even by a newline (‘\n’).


 2 Mapping

 It takes a set of data and converts into another set of data. Where individual elements into tuples (Key-Value pair).


3 Intermediate splitting

The entire process in parallel on different clusters. To group them in “Reduce Phase” the similar KEY data should be on the same cluster.


4 Reduce

It is nothing but group by phase


5 Combining

 Where all the data is combining together to form a Result

 MapReduce Word Counting Example

 1. Mapper Program
2. Reducer Program
3. Client Program


 1. Mapper Program


Create a “WordCountMapper” Java Class which extends Mapper class as shown below


Package com.journaldev.hadoop.mrv1.wordcount;
import org.apache.hadoop.mapreduce.Mapper;
public class WordCountMapper extends Mapper<LongWritable, Text, Text, IntWritable>
public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException
String w = value.toString();
context.write(new Text(w), new IntWritable(1));

Code Explanation


WordCountMapper class has implemented Hadoop, MapReduce API class “Mapper”.

Mapper class has defined by using Mapper<LongWritable, Text, Text, IntWritable>.

 Here <LongWritable, Text, Text, IntWritable>.

<LongWritable, Text> represents Input Data types to our WordCount’s Mapper First one.


 For Example

 We will give a File (Huge amount of Data, any format). Mappers read each line from this file and give one unique number as shown below

 <Unique_Long_Number, Line_Read_From_Input_File>

In Hadoop MapReduce API, it is equal to <LongWritable, Text>.

<Text, IntWritable> represents Output Data types of our Word Count’s Mapper of Second one.


 For Example


Word Count’s Mapper Program gives output as shown below

<Unique_Word_From_Input_File, Word_Count>
In Hadoop MapReduce API is equal to <Text, IntWritable>.

We have implemented Mapper’s map() method and provided our Mapping Function logic here.


 2. Reducer Program


Create a “WordCountReducer” Java Class extends Reducer class as shown below

 package com.journaldev.hadoop.mrv1.wordcount;
import org.apache.hadoop.mapreduce.Reducer;
public class WordCountReducer extends Reducer<Text, IntWritable, Text, IntWritable>
public void reduce(Text key, Iterable<IntWritable> values,Context context) throws IOException, InterruptedException
int sum = 0;
for (IntWritable val : values)
sum += val.get();
context.write(key, new IntWritable(sum));

 Code Explanation


WordCountReducer class has extended Hadoop, MapReduce API class “Reducer”.

Reducer class has defined by using Mapper<Text, IntWritable, Text, IntWritable>
Here <Text, IntWritable, Text, IntWritable>.

First two represents <Text, IntWritable> Input Data types WordCount’s Reducer Program .


For Example


Mapper Program <Text, IntWritable> output, the input of Reducer Program

<Unique_Word_From_Input_File, Word_Count>
In Hadoop MapReduce API, it is equal to <Text, IntWritable>.

Last Two represents <Text, IntWritable> Output Data types Word Count’s Reducer Program.


For Example


Word Count’s Reducer Program gives output as shown below

<Unique_Word_From_Input_File, Total_Word_Count>
In Hadoop MapReduce API. it is equal to <Text, IntWritable>.

We have implemented Reducer reduce () method and provided our Reduce Function.


 3. Client Program


Create a “WordCountClient” Java Class with main() method as shown below

package com.journaldev.hadoop.mrv1.wordcount;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.mapreduce.Job;
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;
public class WordCountClient
public static void main(String[] args) throws Exception
Job job = Job.getInstance(new Configuration());
FileInputFormat.setInputPaths(job, new Path(args[0]));
FileOutputFormat.setOutputPath(job, new Path(args[1]));
boolean status = job.waitForCompletion(true);
if (status)
else {

  Code Explanation


 . Hadoop, MapReduce API has “Job” class at “org.apache.hadoop.mapreduce” package.

. Job Class is creating Jobs to perform our Word Counting tasks.

 . The client program is using Job Object’s methods to set all MapReduce Components. Like Mapper, Reducer, Input Data Type and Output Data type.

. These Jobs will perform Word Counting Mapping and Reducing tasks.


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