Autoboxing and Unboxing in Java: A Simple Guide for Beginners

Learn what autoboxing and unboxing are in Java, why they matter, and how they simplify working with primitive types and wrapper classes. Includes simple examples.

What Are Autoboxing and Unboxing?

In Java, primitive types like int, double, and boolean are not objects — they are basic types.

Java also provides wrapper classes like Integer, Double, and Boolean that wrap these primitives in objects.

Autoboxing:

Automatic conversion of a primitive into its wrapper class.

int num = 5;
Integer obj = num;  // Autoboxing: int → Integer

🔹 Unboxing:

Automatic conversion of a wrapper class object back to a primitive.

Integer obj = 10;
int num = obj;  // Unboxing: Integer → int

🔧 Why Do We Need It?

Before Java 5, you had to do this manually:

int num = 5;
Integer obj = Integer.valueOf(num); // Manual boxing

int result = obj.intValue();        // Manual unboxing