Hadoop is run on Linux kernel. If you want to install Hadoop
on windows OS, Cygwin need to install in your machine.

Cygwin is creating linux like environment in windows. Here
is the link to get cygwin. https://cygwin.com/install.html

Hadoop can be installed in Multi Node cluster / single node
cluster. any one we choose.

In this blog I posted Installation of single node cluster in your machine on Linux
OS.

Step 1: 

Java is mandatory to run Hadoop so check whether
java is installed or not in your machine.

To check for
java

          $java –version

If you want to install Java in linux OS follow the below.

Step2:

$Sudo apt-get install
oracle-java8-installer

Step3:

Hadoop requires SSH access to manage its nodes, i.e. remote
machines plus your local machine where Hadoop runs. For single node cluster
need to configure SSH access to local host for user.

Generate a public key 

$ssh-keygen -t rsa -P ""

Then you have to enable access
to your local machine.

$cat ~/.ssh/id_rsa.pub >>
~/.ssh/authorized_keys

Step4:

Hadoop is free source from Apache software foundation go to
that site and down load the Hadoop latest version which suitable to your
machine.

Extract the downloaded tar file.

$tar xvfz hadoop-1.2.1.tar.gz

After extracting it do some following changes under Hadoop/conf.

Change 1:

Core-site.xml:

<configuration>

     <property>

         
<name>hadoop.tmp.dir</name>

          <value>TEMPORARY-DIR-FOR-HADOOPDATASTORE</value>

           <description>A base for other
temporary directories</description>

    </property>

    <property>

        
<name>fs.default.name</name>

        
<value>hdfs://localhost:54310</value>

    </property>

</configuration>

Change2:

Mapared-site.xml:

<configuration>

<property>

         
<name>mapred.job.tracker</name>

         
<value>localhost:54311</value>

</property>

</configuration>

Change3:

Hdfs-site.xml:

<configuration>

<property>

         
<name>dfs.replication</name>

          <value>1</value>

</property>

</configuration>

Step4:

Conf/slaves change to
localhost

Step5:

Conf/master change to
localhost

         

Step6:

Iit is essential to Setting up the environment
variables for Hadoop and Java

For Temporary set up run
the below command:

$export
JAVA_HOME=/usr/lib/jvm/jdk1.8.0

$export
HADOOP_COMMON_HOME=/home/hadoop/hadoop-install/hadoop-1.2.1

For permanent setting:

Open .bashrc and type end of the file append
the below lines.

To open bashrc

 $gedit ~/.bashrc

And type the below two
lines

$export
JAVA_HOME=/usr/lib/jvm/jdk1.8.0

$export
HADOOP_COMMON_HOME=/home/hadoop/hadoop-install/hadoop-1.2.1

Once done the above run
the below command.

$source ~/.bashrc

Step 7:

Format the Hadoop file
system in Hadoop directory.

$./bin/hadoop namenode –format

Step 8:

Running the cluster.

$./bin/start-all.sh

Step 9:

To stop the cluster.

$./bin/stop-all.sh

 

Inheritance:

Inheritance
is an ability to derive new classes from existing classes. A derived class is
known as subclass which inherits the instance variables and methods of the
super class or base class, and can add some new instance variables and methods.You are not limited to
just one layer of inheritance. The inheritance tree, or class hierarchy can be as deep
as needed. Methods and variables are inherited down through the levels. In general,
the farther down in the hierarchy a class appears, the more specialized its behavior.

Inheritance defines is-a relationship between a Super class and its Sub class.

Inheritance may have
different forms.

Types
of Inheritance:

Single
Inheritance: In this type a sub class can have only one super class.

Single Inheritance

Multiple
Inheritance: In this type of inheritance can have several super classes for a sub
class.

Multiple Inheritance

 

 

Multilevel
Inheritance: This type is derived from another sub class.

Multilevel Inheritance

Hierarchical Inheritance:  This form has one super class and many sub
classes.

Hierarchical Inheritance

 Java Does not support Multiple Inheritance why? Because java is simple, easy in case if java supports multiple inheritance it leads to complexity so to avoid that java does not support multiple inheritance.

 Demonstrate Inheritance in Java:

class Vehicle
{
    String typeOfVehicle;
}
public class Car extends Vehicle {
   
    String modelType;
    public void showDetail()
    {
        typeOfVehicle= "Car";        //accessing Vehicle class member
        modelType = "sports";
        System.out.println(modelType+" "+typeOfVehicle);
    }
    public static void main(String[] args)
    {
        Car car =new Car();
        car.showDetail();
    }
}

Output of the above program:

Sports car