What will be the output of the following Java code?

import java.util.*;
class properties 
{
    public static void main(String args[]) 
    {
        Properties obj = new Properties();
        obj.put("AB", new Integer(3));
        obj.put("BC", new Integer(2));
        obj.put("CD", new Integer(8));
        System.out.print(obj.keySet());
    }
}

What is the purpose of the Java Collections Framework?

A. To provide a unified architecture for representing and manipulating collections

B. To provide a way to create arrays

C. To define primitive data types

D. To handle exceptions

Which interface in the Java Collections Framework represents an ordered collection of elements that can contain duplicate values?

A. `Collection`

B. `Map`

C. `Set`

D. `List`

What is the primary difference between a `List` and a `Set` in the Java Collections Framework?

A. A `Set` allows duplicate elements, while a `List` does not

B. A `List` is unmodifiable, while a `Set` is modifiable

C. A `List` allows duplicate elements, while a `Set` does not

D. A `Set` is indexed, while a `List` is not

Which class is typically used to implement a `List` in the Java Collections Framework?

A. `HashMap`

B. `ArrayList`

C. `LinkedList`

D. None of These