Updated June 27, 2023
Introduction to Inheritance Interview Questions and Answers
Inheritance is a trendy and common word for all the techies who belong from a development background. This feature represents one of the core aspects of the object-oriented programming paradigm, popularly known as OOPs. Many programming languages, such as Java, C++, Lisp, Perl, Python, Scala, etc., support inheritance in some way or the other.
The core fundamental idea behind inheritance is using classes and objects that acquire other entities’ similar properties, thereby reducing the additional effort of reprogramming and rebuilding that piece of code. This helps keep tfile short, precise, crisp, and of a comparatively lower cost concerning space-time complexity. This article will present a list of inheritance interview questions for you.
If you are looking for a job related to Inheritance, you must prepare for the 2023 Interview Questions. Every interview is indeed different as per the various job profiles. Here, we have prepared the critical Inheritance Interview Questions and Answers to help you succeed in your interview.
This 2023 Inheritance Interview Questions article will present the ten most important and frequently asked Inheritance interview questions. These questions are divided into two parts as follows:
Part 1 – Inheritance Interview Questions (Basic)
This first part covers basic Inheritance Interview Questions and Answers.
Q1. What are the different other OOPs techniques apart from inheritance? Why are multiple inheritances not supported by the Java language?
Answer:
Different Object-Oriented Programming techniques are Abstraction, Encapsulation, and Polymorphism. Java supports many other features but not multiple inheritances because it would create ambiguity, confusion, and chaos. Let’s give you more insight into it by using an example.
Suppose we have created two classes, A and B, with the same method name: hello(), and we have also created another class, C, which is extending/inheriting the characteristics and the properties of the classes of A, B. Now, the java ctypes will not understand the hello() method, which is extended by the class C is the result of which class, which calls for ambiguity.
Q2. Why can’t you inherit a constructor?
Answer:
When we say that we can’t inherit a constructor, a subclass instance cannot be created using any superclass constructors. You cannot do this because you do not want a superclass constructor’s properties overridden. This would have been possible if the inheritance was in the picture, but it is not because doing that would conflict with another concept known as Encapsulation.
Q3. Explain the differences between inheritance and composition.
Answer:
The difference between inheritance and composition are as below:
|
S.No. |
Inheritance |
Composition |
|
1. |
The IS-A relationship defines it. | The HAS-A relationship defines it. |
|
2. |
The base class holds a definition of the derived object, establishing a tight coupling between them. | The composed object maintains an external reference to the composing classes, resulting in a loosely coupled relationship in composition. |
|
3. |
Runtime polymorphism | Dependency Injection |
|
4. |
Unit classes can only inherit single classes. | You can compose unit class components with multiple classes at a time. |
|
5. |
Relationship among classes | Relationship among objects |
Q4. Explain the usage of inheritance.
Answer:
These are the basic Inheritance Interview Questions asked in an interview. Classes are extended, whereas interfaces are implemented in case of inheritance; there is a slight variation in the above definition. An interface extends an interface, and a class implements an interface in case of inheritance. The class/interface, which is the derivative one, is also known as the subclass or child class, or base class, and the parent class is also known as the superclass, which provides its properties to the class extending it.
Q5. Can multiple interfaces be implemented? Can a single interface extend multiple interfaces?
Answer:
Yes, that is possible. For example, properties such as Serializable and Comparability can coexist in a class; therefore, this feature can also promote polymorphism. Yes, a single interface is capable of extending multiple interfaces. To cite an example, the interface java.util.The list extends both the Iterable and Collection interface.
Part 2 – Inheritance Interview Questions (Advanced)
Let us now have a look at the advanced Interview Questions.
Q6. Why can private methods not be overridden?
Answer:
The subclass did not inherit a private method’s properties, so it cannot be overridden. Moreover, this kind of method is invisible to all the entities operating outside the class, and the call to it is taken care of at the compile time itself by making use of Type.
Q7. In the context of inheritance, java.lang. The object class is one major class with which all other java classes are inherited. Comment on the inheritance for interfaces. Are Object classes responsible for their inheritance?
Answer:
In Java, classes can inherit from other classes, specifically object classes, while interfaces do not provide inheritance to classes. On the contrary, the classes responsible for implementing interfaces have their root level of inheritance from Object classes.
Q8. Can the subclass inherit static members?
Answer:
No, an inheritance of static members is impossible, but the subclass and the superclass can both consist of the static method with a common signature. The subclass will consist of the properties of the static member of the superclass.
Q9. Explain the different types of inheritance.
Answer:
These are the popular Inheritance Interview Questions asked in an interview. Different kinds of inheritance are:
- Single Inheritance: In this type of inheritance, other single classes extend the properties of a single class.
- Hierarchical Inheritance: In this kind of inheritance, multiple classes extend a single class.
- Multilevel Inheritance: In the case of multilevel inheritance, a class is inherited by a class which again is inherited by another class, forming a multilevel chaining mechanism of inheritances.
- Multiple Inheritance (Not supported for classes in Java): When a single class extends multiple classes, it exhibits a combination of the mentioned inheritance types. One can achieve this by utilizing interfaces.
- Hybrid Inheritance: (Not supported for classes in Java): A class can derive from more than one class in multiple inheritance, combining multilevel inheritance and multiple inheritances. In this scenario, the derived class is considered the parent class, rather than the base class.
Q10. Is it possible to downgrade the visibility of an overridden or an inherited method?
Answer:
No, reducing visibility is not possible.
Conclusion
In this post, we read about inheritance interview questions. These questions aim to provide you with a comprehensive understanding of the concepts related to inheritance. There are other underlying features of object-oriented programming language which the interviewer could ask. Apart from just concepts, you should also prepare to solve any code outputs and debug inheritance-related questions. I hope you liked this article. Keep following us for plenty of other good articles about various technology.
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