Java Summer Internship Quiz-11

What is the significance of the Object class in Java?

• A) It is the root class of all classes in Java.

• B) It is a utility class for common operations.

• C) It is the superclass of only primitive data types.

• D) It is used only for typecasting.

What is the default implementation of the hashCode() method in the Object class? .

• A) It returns the memory address of the object

• B) It returns a random integer.

• C) It returns a unique identifier for the object.

• D) It is not implemented in the Object class.

Why is it important to override both the equals() and hashCode() methods together?

• A) It ensures that equals() can be used with primitive data types.

• B) It prevents memory leaks in the application.

• C) It maintains the contract between equals() and hashCode() for hash-based data structures.

• D) It improves the performance of the application.

What is the return type of the getClass() method in the Object class?

• A) Object

• B) Class

• C) Type

• D) Class<?>

What is the purpose of the toString() method in the Object class?

• A) It converts an object to a string representation.

• B) It provides the memory address of the object.

• C) It compares two objects for equality.

• D) It converts a string to an object.

How can you prevent a class from being subclassed in Java?

• A) Make the class private.

• B) Use the final keyword in the class declaration.

• C) Override the Object class.

• D) Use the sealed keyword.

When comparing two objects for equality using the == operator, what are you actually comparing?

• A) The content of the objects.

• B) The memory addresses of the objects.

• C) The overridden equals() method.

• D) The hashCode() values of the objects.

What is the value of “d” in the following Java code snippet?

double d = Math.round ( 2.5 + Math.random() );

• a) 2

• b) 3

• c) 4

• d) 2.5

What will be the output of the following Java program?

class Output{

public static void main(String args[]){

int x = 3.14;

int y = (int) Math.abs(x);

System.out.print(y);

}

}

• a) 0

• b) 3

• c) 3.0

• d) 3.1

What will be the output of the following Java program?

class Output{

public static void main(String args[]) {

double x = 3.1;

double y = 4.5;

double z = Math.max( x, y );

System.out.print(z);

}

}

• a) true

• b) flase

• c) 3.1

• d) 4.5