OOP Q7

Which keyword is used to achieve encapsulation in Java?

• A) private

• B) protected

• C) public

• D) All of the above

Consider the following class. What is the purpose of the setSpeed method?

• A) To set the speed field to any value

• B) To restrict setting the speed field to non-negative values

• C) To get the value of the speed field

• D) To print the speed field

What will be the result of attempting to compile and run the following code?

• A) null

• B) John

• C) Compilation error

• D) Runtime error

What is encapsulation in Java?

• A) A process of combining methods and data members in a single unit

• B) A process of hiding the implementation details and exposing only the functionality

• C) A process of inheriting methods from a superclass

• D) A process of overriding methods in a subclass

What does it mean for a class to be tightly encapsulated?

• A) All its fields are private, and it provides public getter and setter methods for them

• B) All its fields and methods are public

• C) It does not have any constructors

• D) It cannot be inherited

What is the main advantage of encapsulation?

• A) It allows direct access to the data

• B) It makes the class methods private

• C) It enhances code maintenance and flexibility

• D) It prevents class inheritance

Which of the following statements is true about encapsulation?

• A) It requires all methods to be private

• B) It requires all classes to be public

• C) It allows a class to control how its data is accessed and modified

• D) It prevents the use of inheritance

What is the purpose of the this keyword in setter methods?

• A) To refer to the method parameter

• B) To refer to the current class instance

• C) To refer to a static variable

• D) To refer to a superclass method

Why should fields typically be declared private in a class?

• A) To allow direct access to the fields

• B) To prevent direct access and modification from outside the class

• C) To enable inheritance

• D) To make the fields accessible to all other classes

How can encapsulation help improve security in a Java application?

• A) By making all methods public

• B) By restricting access to the class's internal state

• C) By using inheritance

• D) By avoiding the use of classes