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Selenium - Core Java OOPs Concept - Inheritance (Reusability)
Advantages of re-usability:
1. Save time and effort
2. Maintenance of code is easy means if you want to modify the code. We will change the code in one place.
OOPs Concept Inheritance:
1. The objective of inheritance is re-usability.
2. The process of acquiring the methods and variables from Super-class to Sub-Class is called Inheritance.
Class members are methods and variables.
Two types of class members -> static and nonstatic
Static Members are accessed using Class Name:
public static void display()
{
}
Non-Static Members are accessed using Object:
public void display()
{
}
Only object level class members are inherited to subclass.
3. Inheritance is achieved between two classes using the keyword called 'extends'. From now on-wards 'extends' means inheritance.
4. Single Inheritance is between two classes is achieved using the extends keyword
Class A
{
public int i=20;
public void display()
{
}
}
Class B extends ClassA
{
}
5. Multilevel Inheritance : mean the subclass(child) can access superclass(Father) and Superclass SuperClass (GrandFather) also.
Class A
{
}
Class B extends Class A
{
}
Class C extends Class B
{
}
6. Multiple Inheritance:
In java we cannot extend more than one class at a time.
Multiple classes cannot be inherited at the same time.
So, multiple inheritance is not supported in java.
Class C extends Class B,Class A //Not Valid in java
Diamond Problem in java.
7. By Default a Class extends Object Class. So we can access the object class Members. Object is a class available in the package java.lang.
8. Only non-static variables and methods are inherited to the subclass. Static variables and Methods are at the class level not at the object level. So cannot be inherited to the subclass.
9. Global and Local Variables
public class Variables {
int a = 20; // Global variable
public static void main(String[] args) {
int a =10;
System.out.println(a); // local variable
Variables v = new Variables();
System.out.println(v.a);
}
}
1. Save time and effort
2. Maintenance of code is easy means if you want to modify the code. We will change the code in one place.
OOPs Concept Inheritance:
1. The objective of inheritance is re-usability.
2. The process of acquiring the methods and variables from Super-class to Sub-Class is called Inheritance.
Class members are methods and variables.
Two types of class members -> static and nonstatic
Static Members are accessed using Class Name:
public static void display()
{
}
Non-Static Members are accessed using Object:
public void display()
{
}
Only object level class members are inherited to subclass.
3. Inheritance is achieved between two classes using the keyword called 'extends'. From now on-wards 'extends' means inheritance.
4. Single Inheritance is between two classes is achieved using the extends keyword
Class A
{
public int i=20;
public void display()
{
}
}
Class B extends ClassA
{
}
5. Multilevel Inheritance : mean the subclass(child) can access superclass(Father) and Superclass SuperClass (GrandFather) also.
Class A
{
}
Class B extends Class A
{
}
Class C extends Class B
{
}
6. Multiple Inheritance:
In java we cannot extend more than one class at a time.
Multiple classes cannot be inherited at the same time.
So, multiple inheritance is not supported in java.
Class C extends Class B,Class A //Not Valid in java
Diamond Problem in java.
7. By Default a Class extends Object Class. So we can access the object class Members. Object is a class available in the package java.lang.
8. Only non-static variables and methods are inherited to the subclass. Static variables and Methods are at the class level not at the object level. So cannot be inherited to the subclass.
9. Global and Local Variables
public class Variables {
int a = 20; // Global variable
public static void main(String[] args) {
int a =10;
System.out.println(a); // local variable
Variables v = new Variables();
System.out.println(v.a);
}
}
1 comments:
Thanks for sharing this good blog.This is very important and imformative blog for Java .It's very interesting and useful for students
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