JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD MCA JAVA PROGRAMMING Previous Question Paper (March/April - 2022 - R13)

Constructor overloading is a technique in Java that allows a class to have multiple constructors with different parameter lists. The compiler differentiates these constructors based on the number, type, and order of the parameters provided during object creation. This provides flexibility in initializing objects with different sets of data.

Example:

class Student {
    String name;
    int age;

    // Constructor with no arguments
    Student() {
        name = "Unknown";
        age = 0;
    }

    // Constructor with two arguments
    Student(String n, int a) {
        name = n;
        age = a;
    }
}

Autoboxing is the automatic conversion that the Java compiler makes between the primitive types and their corresponding object wrapper classes (e.g., converting an int to an Integer). This process simplifies code by allowing developers to use primitive values where an object is expected, such as in collections.

Example:

// Autoboxing: primitive int assigned to Integer object
Integer num = 10;

// Using in a collection
java.util.ArrayList<Integer> list = new java.util.ArrayList<>();
list.add(25); // The primitive 25 is automatically boxed into an Integer object