what is the difference between abstract class and
Interface?where we can use it in realtime projects?
Answer Posted / chitij mehrotra
1 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 ? | 54 Yes | 6 No |
Post New Answer View All Answers
Is char a data type in java?
List some oops concepts in java?
Can an object subclass another object?
When we should use serialization?
Explain about main thread in java?
What are java methods?
What is linked hashmap and its features?
What is java dot?
What is meant by method?
What is immutable class in java?
What is size () in java?
What is the properties class?
What is the constructor?
Why is it called buffering?
What does microservices mean?