What is Type Casting in Java?

Type casting means converting one data type into another data type.

Java automatically converts smaller data types into larger data types, but converting larger types into smaller types must be done manually.

Types of Type Casting

Java supports two types of casting:

Widening Casting (Automatic Casting)
Narrowing Casting (Manual Casting)

Widening Casting

Widening casting converts a smaller data type into a larger data type automatically.

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

Example of Widening Casting

public class Main {

    public static void main(String[] args) {

        int number = 100;

        double value = number;

        System.out.println(number);

        System.out.println(value);

    }

}

Output

100
100.0

Java automatically converts int into double.

Narrowing Casting

Narrowing casting converts larger data types into smaller data types manually.

This process may cause data loss.

Example of Narrowing Casting

public class Main {

    public static void main(String[] args) {

        double price = 99.99;

        int number = (int) price;

        System.out.println(price);

        System.out.println(number);

    }

}

Output

99.99
99

Decimal value is lost after converting double into int.

Type Casting Syntax

Automatic Casting

largerType variable = smallerTypeVariable;

Manual Casting

smallerType variable = (smallerType) largerTypeVariable;

byte to int Example

byte age = 25;

int value = age;

System.out.println(value);

int to double Example

int marks = 90;

double total = marks;

System.out.println(total);

double to int Example

double salary = 45678.99;

int amount = (int) salary;

System.out.println(amount);

Character Type Casting

Characters can also be converted into integers.

char letter = 'A';

int value = letter;

System.out.println(value);

Output

Java stores characters using Unicode values.

int to char Example

int number = 66;

char letter = (char) number;

System.out.println(letter);

Output

Data Loss in Narrowing Casting

Narrowing casting may lose information if larger value does not fit into smaller type.

int number = 130;

byte value = (byte) number;

System.out.println(value);

Output

-126

Real Life Example

double billAmount = 999.99;

int finalAmount = (int) billAmount;

System.out.println(finalAmount);

Complete Java Type Casting Program

public class Main {

    public static void main(String[] args) {

        int age = 25;

        double value = age;

        System.out.println(value);

        double marks = 89.5;

        int total = (int) marks;

        System.out.println(total);

        char letter = 'A';

        int unicode = letter;

        System.out.println(unicode);

    }

}

Output

25.0
89
65

Advantages of Type Casting

Helps convert compatible data types
Useful in calculations
Improves flexibility in programming
Supports memory optimization

Common Errors

Forgetting manual casting
Loss of decimal values
Overflow in narrowing casting
Using incompatible data types

Best Practices

Use widening casting whenever possible
Avoid unnecessary narrowing casting
Check for data loss carefully
Use meaningful variable names

Conclusion

Type casting is an important concept in Java programming. It helps developers convert data types for calculations, memory management, and program flexibility.