Practice Object Oriented Programming Questions and Answers

• What is the primary goal of Abstraction in OOP?
• Which of the following is a common mechanism to achieve abstraction in OOP?
• An abstract class in Java/C++:
• What is an interface in OOP (e.g., Java, C#)?
• Which statement about abstract methods is true?
• How does abstraction contribute to code maintainability?
• Which of the following best represents a real-world example of abstraction?
• What is the primary difference between an abstract class and an interface in Java (pre-Java 8)?
• If a class contains an abstract method, what must be true about the class itself?
• Which OOP principle is most closely related to the concept of "information hiding"?
• What is Encapsulation in OOP?
• Which access modifier is most commonly used to achieve data hiding in encapsulation?
• What are "getter" and "setter" methods primarily used for in the context of encapsulation?
• Which of the following is a benefit of encapsulation?
• Consider a BankAccount class with a balance field. To properly encapsulate balance, it should be declared as:
• Which of the following is the correct way to handle exceptions in Java?
• In Java, what is the difference between '==' and '.equals()' when comparing String objects?
• What does the following Java code snippet demonstrate? class Animal {     void sound() { System.out.println("Some sound"); } } class Dog extends Animal {...
• What is the purpose of the 'static' keyword in Java?
• In .NET (C#), what is the difference between 'struct' and 'class'?
• What is 'recursion' in programming?
• Which of the following is not a valid type of inheritance in Java?
• Which of the following statements is incorrect in reference to Java?
• Which Object-Oriented Programming principle allows a subclass to provide its own specific implementation of a method that is already defined in its supercl...
• In Java, which keyword, when applied to a class declaration, prevents that class from being extended (inherited) by any other class?
• Which Object-Oriented Programming principle refers to bundling data (attributes) and the methods that operate on that data into a single unit, while restri...
• Which type of inheritance allows a class to inherit properties and behavior from more than one parent class simultaneously — supported directly in C++, b...
• Which statement about constructors in Object-Oriented Programming languages such as C++ or Java is correct?
• In C++, class D inherits from both class B and class C, and both B and C separately inherit from a common base class A (without using virtual inheritance)....
• A C++ base pointer refers to a derived object. The base function is virtual and overridden. What happens when called through the base pointer?
• A class exposes calculateSalary() while hiding internal rules and data. Which OOP concept is best illustrated?
• What is the output of the following Java code? class Counter {     static int count = 0;     Counter() { count++; } } public class Main {     public ...
• Which OOP concept allows a single function or method name to behave differently based on the number or type of arguments passed to it?
• What is the primary purpose of a "constructor" in object-oriented programming?
• Which statement best distinguishes a "class" from an "object" in object-oriented programming?