Is lesson me hum seekhenge:

• Wrapper class kya hoti hai
• Primitive vs Wrapper difference
• Autoboxing & Unboxing
• Important wrapper classes
• Use cases aur examples

Wrapper class ka matlab:

primitive data type ko object me convert karna

Java me har primitive type ka ek wrapper class hota hai.

Java me kuch features:

sirf objects ke saath kaam karte hain

Example:

Collections Framework
ArrayList

Isliye primitives ko object banana padta hai.

Autoboxing ka matlab:

primitive → object conversion automatically

Example:

public class Test {

    public static void main(String[] args){

        int a = 10;

        Integer obj = a; // autoboxing

        System.out.println(obj);
    }
}

Unboxing ka matlab:

object → primitive conversion

Example:

Integer obj = 20;

int num = obj; // unboxing

System.out.println(num);

int a = 10;

Integer obj = Integer.valueOf(a);

int num = obj.intValue();

Example with Integer:

Integer num = 100;

System.out.println(num.toString());
System.out.println(num.compareTo(50));
System.out.println(Integer.parseInt("123"));

String str = "50";

int num = Integer.parseInt(str);

System.out.println(num + 10); // 60

int num = 100;

String str = String.valueOf(num);

import java.util.ArrayList;

class Test {

    public static void main(String[] args){

        ArrayList<Integer> list = new ArrayList<>();

        list.add(10); // autoboxing
        list.add(20);

        for(Integer n : list){
            System.out.println(n); // unboxing
        }
    }
}

✔ Wrapper classes immutable hoti hain
✔ null value store kar sakti hain (primitive nahi)
✔ collections me required hoti hain

Wrapper slower hota hai primitive se

Kyunki:

object creation + memory overhead

1. Wrapper class kya hoti hai?
2. Autoboxing aur unboxing kya hai?
3. Primitive aur wrapper me difference?
4. Collections me primitive kyun use nahi hota?

Is lesson me humne seekha:

✔ Wrapper class concept
✔ Primitive vs object difference
✔ Autoboxing & Unboxing
✔ Conversion methods
✔ Real-life usage

Wrapper classes Java me primitive aur object world ke beech bridge ka kaam karti hain.