Java Type Casting

Java Type Casting (Type Conversion)

Type casting in Java is the process of converting a variable from one data type to another. There are two types of type casting:

✅ 1. Widening Casting (Automatic / Implicit Conversion)

Converts a smaller type → larger type automatically.
No data loss occurs.

From	To
byte → short → int → long → float → double

Example:

public class Main {
public static void main(String[] args) {
int myInt = 10;
double myDouble = myInt; // Automatic casting: int → double

System.out.println(myInt); // Output: 10
System.out.println(myDouble); // Output: 10.0
}
}

public class Main {

public static void main(String[] args) {

int myInt = 10;

double myDouble = myInt; // Automatic casting: int → double

System.out.println(myInt); // Output: 10

System.out.println(myDouble); // Output: 10.0

}

🚀 2. Narrowing Casting (Manual / Explicit Conversion)

Converts a larger type → smaller type manually.
May result in data loss.

Example:

public class Main {
public static void main(String[] args) {
double myDouble = 10.99;
int myInt = (int) myDouble; // Manual casting: double → int

System.out.println(myDouble); // Output: 10.99
System.out.println(myInt); // Output: 10
}
}

public class Main {

public static void main(String[] args) {

double myDouble = 10.99;

int myInt = (int) myDouble; // Manual casting: double → int

System.out.println(myDouble); // Output: 10.99

System.out.println(myInt); // Output: 10

}

🎯 Important Notes

Widening Casting is safe since Java handles it automatically.
Narrowing Casting may lose precision, especially with decimals.

Additional Example:

public class Main {
public static void main(String[] args) {
byte b = 50;
int i = b; // widening
byte c = (byte)i; // narrowing

System.out.println("byte b: " + b);
System.out.println("int i: " + i);
System.out.println("byte c: " + c);
}
}

public class Main {

public static void main(String[] args) {

byte b = 50;

int i = b; // widening

byte c = (byte)i; // narrowing

System.out.println("byte b: " + b);

System.out.println("int i: " + i);

System.out.println("byte c: " + c);

}

🎉 Summary Table

Type	Type Casting	Automatic?	Risk
Widening	Small → Large	Yes	No
Narrowing	Large → Small	No	Yes (data loss)

Java Type Casting