Abstract Coding Interview Questions For Beginners

Programming questions are an integral part of an interview for the developers position. No matter which programming language you master, familiarity with fundamental concepts of programming is something that is always expected from you.

Coding skills are always the deciding factor in any programming interview. In this coding interview questions article, we will discuss the top 40 Coding Interview Questions you should absolutely know to crack those interviews and get your dream job.

The coding interview questions addresses in this article are grouped into 2 categories (as below) to make your learning simpler.

Question: What is abstraction and abstract class in Java?


Abstraction is a process of hiding the implementation details and showing only functionality to the user.

Another way, it shows only important things to the user and hides the internal details for example sending sms, you just type the text and send the message. You dont know the internal processing about the message delivery.

Abstraction lets you focus on what the object does instead of how it does it.

There are two ways to achieve abstraction in java

Abstract class (0 to 100%) Interface (100%)

Abstract class in Java:

A class that is declared as abstract is known as abstract class. It needs to be extended and its method implemented. It cannot be instantiated.

Abstract method:

A method that is declared as abstract and does not have implementation is known as abstract method. Example abstract method

Question: Can you create instance of abstract class?

No, you can not create instance of abstract class in Java, they are incomplete.

Even though, if your abstract class don’t contain any abstract method, you can not create instance of it.

By making a class abstract, you told compiler that, it’s incomplete and should not be instantiated. Java compiler will throw error, when a code tries to instantiate abstract class.

2 How do you reverse a string in Java?

  • Declare a string.
  • Take out the length of that string.
  • Loop through the characters of the string.
  • Add the characters in reverse order in the new string.
  • 2 How to find out if the given two strings are anagrams or not?

    Two strings are anagrams if they contain a similar group of characters in a varied sequence.

  • Declare a boolean variable that tells at the end of the two strings are anagrams or not.
  • First, check if the length of both strings is the same, if not, they cannot be anagrams.
  • Convert both the strings to character arrays and then sort them.
  • Check if the sorted arrays are equal. If they are equal, print anagrams, otherwise not anagrams.Â
  • Â Â Â Â System.out.println(str + ” and ” + reverse + ” not anagrams string”);

    Â Â Â Â char[] anagram1 = str.toCharArray();

    Â Â Â Â char[] anagram2 = reverse.toCharArray();

    Â Â Â Â anagrmstat = Arrays.equals(anagram1, anagram2);

    Â Â Â Â System.out.println(” anagrams string”);

    Â Â Â Â System.out.println(” not anagrams string”);

    1 Which sorting algorithm is the best?

  • There are many types of sorting algorithms: bubble sort, quick sort, balloon sort, merge sort, radix sort, and more.
  • No algorithm can be considered as the best or fastest because they have designed each for a specific type of data structure where it performs the best
  • 1 What are the concepts introduced in OOPs?

    Following are the concepts introduced in OOPs:

  • Object – A real-world entity having a particular state and behavior. We can define it as an instance of a class.
  • Class – A logical entity that defines the blueprint from which an object can be created or instantiated.
  • Inheritance – A concept that refers to an object gaining all the properties and behaviors of a parent object. It provides code reusability.
  • Polymorphism – A concept that allows a task to be performed in different ways. In Java, we use method overloading and method overriding to achieve polymorphism.
  • Abstraction – A concept that hides the internal details of an application and only shows the functionality. In Java, we use abstract class and interface to achieve abstraction.
  • Encapsulation – A concept that refers to the wrapping of code and data together into a single unit.
  • This is one of the very common coding interview questions, that often allows the interviewer to branch out into related topics based on the candidate’s answers

    Coding Interview Questions And Answers | Programming Interview Questions And Answers | Simplilearn

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