What will be the output of the following Java program?

class box 
{
     int width;
     int height;
     int length;
} 
 class mainclass 
 {
     public static void main(String args[]) 
     {        
         box obj = new box();
         System.out.println(obj);
     } 
 }

What is a constructor in Java?

A. A special method to create instances of classes

B. A method used for mathematical calculations

C. A method to perform string manipulations

D. An exception handling mechanism

Which keyword is used to define a method in Java?

A. method

B. def

C. func

D. public

In Java, which method is automatically called when an object is created?

A. start()

B. main()

C. init()

D. constructor()

What is method overloading in Java?

A. Defining multiple methods with the same name in the same class

B. Calling methods from another class

C. Using methods to load data from a file

D. Running methods in parallel threads