OOP

Question 1

Define a class

Answer 1

A blueprint for creating objects; groups fields & methods.

Question 2

Define an object

Answer 2

An instance of a class.

Question 3

Define a method

Answer 3

Subprogram/code that performs a single task.

Question 4

Give examples of access modifiers.

Answer 4

Private, public, protected.

Question 5

Define a constructor

Answer 5

A special method that assigns values to object fields when created.

Question 6

Define method overloading

Answer 6

Having multiple methods with the same name but different parameter lists in the same class.

Question 7

Define method overriding

Answer 7

Subclass redefines a method from the superclass (same name, same parameters).

Method overriding in Java occurs when a subclass provides a specific implementation for a method that is already defined in its superclass

Question 8

Define encapsulation

Answer 8

Combining attributes and behaviors into a single unit (one class)

Question 9

Explain the reliability of encapsulation

Answer 9

• Promotes information hiding, where internal details of the class are not directly accessibly from the outside class
• Prevents external code from modifying the internal state of an object
• . By encapsulating the internal details, you have more control over the class, making it less prone to unintended misuse

Question 10

Define an accessor method.

Answer 10

A typed method that returns a value from an object.

A method that gets (returns) a field’s value.

Question 11

What does an access modifier do?

Answer 11

Controls visibility of class, method, or variable.

Question 12

Define a mutator method.

Answer 12

A method that changes object fields but does not return a value.

A method that sets or changes a field’s value.

Question 13

What is the purpose of encapsulation?

Answer 13

Protect data by hiding it and controlling access.

Question 14

What is the advantage of OOP

Answer 14

Allows code reuse and easier program design

Question 15

Define inheritance.

Answer 15

A class uses properties and methods from another class.

Question 16

Define method resolution

Answer 16

• the appropriate method will be invoked (called) based on the type of the object declared in another class
• Ability of the programming language / java to determine which
  method to called based on the method signature

Question 17

Define a method signature.

Answer 17

The method name + number and types of parameters.

Question 18

Define a superclass.

Answer 18

The parent class in an inheritance hierarchy.

Question 19

Define a subclass.

Answer 19

A child class that inherits from a parent class.

Question 20

What is a typed method versus a void method?

Answer 20

A typed method returns a value.

A void method does not return any value.

Question 21

What is the difference between static and non static

Answer 21

Static Method - A method that belongs to the entire class instead of one instance of the class.

• Static fields and methods belong to a CLASS.
• Non-static fields and methods belong to an OBJECT

Question 22

Explain why constants are useful in programming

Answer 22

• Constants are useful in programming when a value needs to remain fixed
  throughout the program’s execution.
• They provide a way to give meaningful names
  to fixed values, making the code more readable and maintainable.
• Constants also
  make it easier to update a value in a single place in the code.

Question 23

Define polymorphism

Answer 23

• One method behaving differently based on the object or parameters.
• allows objects of different classes to be treated as objects of a common superclass. This enables a single action to be performed in different ways, based on the specific object being used