Inheritance:  Inheriting parent's properties, all tags and attributes are packaged for your use.
  •  privileges are regulated by the parent or base or super class, these names are synonymous.
Step :1 The code below shows how to create super class, and the scope of the members.

class A
{
public int share_all = 12;
private int share_within = 24;
protected int share_protedted = 48;
public A()
{
System.out.println("Base/Super class A ");
}
public void method_share()
{
}
protected void method_protected()
{
}
private void method_private()
{
int n1 = 20;

}
}
Step 1-Images This symbols are used in Eclipse GUI to compile java codes.
Step 2- Images : Edit the existing code: Note the scope of private field member
Step 3: Create class B, and add the following codes

class B extends A
{
public B()
{
System.out.println("Extended class B Constructor ");
}
}
The complete code of super class A and extended class B.

class A
{
public int share_all = 12;
private int share_within = 24;
protected int share_protedted = 48;
public A()
{
System.out.println("Base/Super class A ");
}
public void method_share()
{
}
protected void method_protected()
{
System.out.println("Only extend class will use it" + share_within);
}
private void method_private()
{
//local won't be seen beyond this method
int n1 =35;
this.share_within = n1;
}
}
class B extends A
{
public B()
{
System.out.println("Extended class B Constructor ");
}
}
Step 4 : calling the classes. the green letters shows how to create an instance of one class in another class with new Key word. But object is not formed. If you run this code in Eclipse

public class test
{
String str = "Helloworld";
public static void main(String[] args) throws IOException

{
InputStreamReader isr = new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(isr);
// needs throws IOException
System.out.print("Type some thing : ");
String str =br.readLine();
B b ;
}
}
Now, if you call this instance of B class, you would notice that none of the extern classes (A or B), were engaged.
Now watch the code, I created an object using new Keyword. Instance of class and object of a class can be created in one line, as shown below.
  • B b = new B():
Notice the difference in the out put generated when we ran this application.
Once the the object from a class created, you are allowed to use the inherited fields and methods members, those are declared as either protected or public. The private members in the base class can't be accessed from the derived class.
 
The completed routine

import java.io.*;
import java.io.IOException;

//javac clas_name.java
public class test
{
String str = "Helloworld";
public static void main(String[] args) throws IOException

{
InputStreamReader isr = new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(isr);
// needs throws IOException
System.out.print("Type some thing : ");
String str =br.readLine();
B b = new B();
System.out.println("The value from Base via derived class :"+ b.share_all);
System.out.println("The value from Base via derived class :"+ b.share_protected);
b.method_protected();
b.method_share();

}
}
class A
{
public int share_all = 12 ;
private int share_within = 24;
protected int share_protected = 48;
public A()
{
System.out.println("Base/Super class A Constructor");
}
public void method_share()
{
}
protected void method_protected()
{
System.out.println("Only extend class will use it" + share_within);
}
private void method_private()
{
//local won't be seen beyond this method
int n1 =35;
this.share_within = n1;
}
}
class B extends A
{
public B()
{
System.out.println("Extended class B Constructor ");
}
}
In the above example Class B inherited all the methods, but never used those methods. To force a method or few methods in the derived class, you can make an abstract base class . The use of abstract class is explained in another example. Link