what is the difference between abstract class and
Interface?where we can use it in realtime projects?
Answer Posted / sachi
A class may inplement several interfaces. A
class may
extend only one abstract class.
2 An interface can have only abstract methods. An
abstract
class can have both abstract methods and concrete methods.
At one abstract method in the abstract class.
3 Interfaces cannot have constructors. Abstract
class can
have constructors.
4 Only static final variables are allowed to be
decelared.
Both static and instance variables are allowed.
5 All decelared methods are implicitly public. Can
have any
kind of methods.
6 We should initialize variables in an interface. Not
necessary to initialize variables in an abstract class.
7 In the case of interface you can make any class in
the
hierarchy. In the case of abstract class you know the
class
hierarchy in advance.
8 An interface implementation may be added to any
existing
third party class. A third party class must be
rewritten to
extend only from the abstract class.
9 Interfaces can be implemented by classes that are
not
related to one another Abstract classes are used only when
there is a “is-a” type of relationship between the classes.
| Is This Answer Correct ? | 18 Yes | 5 No |
Post New Answer View All Answers
What is thread count in java?
Why are the objects immutable in java?
What is a for loop in java?
How many bits is a 64 bit byte?
Which is faster call by value or call by reference?
What is the difference between serializable and externalizable interface?
What is 32 bit float?
Write a program to print all permutations of string?
Is main an identifier?
How many types of interfaces are there?
how its run?
What are implicit objects in java?
What are the different approaches to implement a function to generate a random number?
How can we break singleton in java?
What is difference between fail-fast and fail-safe?