Computer Knowledge

Object-Oriented Programming

2,686 Questions

Object-oriented programming questions test core computer science concepts like classes, inheritance, polymorphism, and encapsulation. The focus includes Java program structures, method overloading, and memory allocation for objects. This topic is essential for technical sections in various recruitment tests.

Java class definitionsMethod overriding rulesPolymorphism conceptsGeneric type parametersMemory allocation in objects

Object-Oriented Programming Questions

Multiple choice

Which of the following is not true about method overriding in java?

  1. In method overriding, the super class and the subclass have a same method name with the same parameters type.

  2. In method overriding, the superclass and subclass have the same return type.

  3. Overriding is a form of runtime polymorphism in java.

  4. We can override the static methods in java.

  5. All of the above
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Yes, all of the above are the true statements.

Multiple choice

Which of the following translates the software requirements into specifications for objects, and derives class hierarchies from which the objects can be created?

  1. Object oriented design

  2. Object oriented analysis

  3. Object oriented programming

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Object oriented design (OOD) translates the software requirements into specifications for objects and derives class hierarchies from which the objects can be created.

Multiple choice

How many constructors are there of ArrayList class in Java?

  1. 6

  2. 5

  3. 4

  4. 3

  5. 2
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This is the correct answer as there are 3 constructors of ArrayList class in Java Collections, viz. ArrayList(): creates an empty constructor with default initial capacity; ArrayList(c : collection): creates an arraylist from existing collection c; and ArrayList(x int): creates an arraylist with initial capacity x. So, this is the correct answer.

Multiple choice

How many constructors are there of Vector class in Java Collections framework?

  1. 6

  2. 5

  3. 4

  4. 3

  5. 2
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is the correct answer. There are 4 constructors of Vector class, viz. Vector(): creates a default vector with initial capacity 10; Vector(c : collections): creates a vector from existing collection; Vector(initialcapacity int): creates a vector with specified initial capacity; and Vector(initialcapacity int,increment int): creates a vector with specified initial capacity and increment. So, this is the correct answer.

Multiple choice

Object is a/an ____________.

  1. entity of the class

  2. instance of the class

  3. attribute of the class

  4. method of the class

  5. function of the class
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is the definition of an object. It uses all the properties of the class.