Abstract classes and Interfaces code example

Example 1: difference between abstract and interface

Interface 
1) Interface contains only abstract methods 
2) Access Specifiers for methods in interface
must be public
3) Variables defined must be public , static ,
final
4) Multiple Inheritance in java is implemented
using interface
5) To implement an interface we use
implements keyword

Abstract Class
1) Abstract class can contain abstract methods,
concrete methods or both
2) Except private we can have any access
specifier for methods in abstract class.
3) Except private variables can have any access
specifiers
4)We cannot achieve multiple inheritance using
abstract class.
5)To implement an interface we use implements
keyword

Example 2: abstract class vs interface

Interfaces specify what a class must do and not how. 
It is the blueprint of the class.
It is used to achieve total abstraction. 

We are using implements keyword for interface.

Abstract=
Sometimes we may come across a situation
where we cannot provide implementation to
all the methods in a class. We want to leave the 
implementation to a class that extends it.
  In that case we declare a class
as abstract by using abstract keyword on method
signature.In my framework I have created my
PageBase class as super
class of the all page classes. 
I have collected all common elements
and functions into PageBase class and
all other page classes extent PageBase class.
By doing so, I don't have to locate very
common WebElements and it provides
reusability in my framework.
Also
1)Abstract classes cannot be instantiated
2)An abstarct classes contains abstract method,
concrete methods or both.
3)Any class which extends abstarct class must
  override all methods of abstract class
4)An abstarct class can contain either
  0 or more abstract method.

Example 3: abstract classes and interfaces in java

abstract class have no implementation of methods functions inside it. the classes which extending abstract class have to implement it

Example 4: abstract classes vs interfaces

Interface 
1) Interface contains only abstract methods 
2) Access Specifiers for methods in interface
must be public
3) Variables defined must be public , static ,
final
4) Multiple Inheritance in java is implemented
using interface
5) To implement an interface we use
implements keyword

Abstract Class
1) Abstract class can contain abstract methods,
concrete methods or both
2) Except private we can have any access
specifier for methods in abstract class.
3) Except private variables can have any access
specifiers
4)We cannot achieve multiple inheritance using
abstract class.
5)To implement an interface we use extends
keyword

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