Java 8 | IntSupplier Interface with Examples

The IntSupplier interface is a specialized functional interface introduced in Java 8 and available in the java.util.function package. It represents a supplier of int values and does not accept any input arguments. It is commonly used when an integer value needs to be generated, calculated, or supplied on demand.

• Primitive specialization of Supplier<Integer>.
• Avoids boxing and unboxing overhead.
• Supports lambda expressions and method references.

import java.util.function.IntSupplier;

public class Main {
    public static void main(String[] args) {

        IntSupplier randomNumber =
            () -> (int) (Math.random() * 100);

        System.out.println(randomNumber.getAsInt());
    }
}

6

Explanation: In this example, the IntSupplier generates a random integer value between 0 and 99. The getAsInt() method retrieves and returns the generated value.

Syntax

@FunctionalInterface
public interface IntSupplier

Return Value: Returns an int value.

Example 1: Generate a Roll Number

import java.util.function.IntSupplier;

public class Main {
    public static void main(String[] args) {

        IntSupplier rollNumber = () -> 101;

        System.out.println("Roll Number: "
                           + rollNumber.getAsInt());
    }
}

Roll Number: 101

Explanation: The IntSupplier supplies a fixed roll number whenever getAsInt() is called.

Example 2: Return Current Year

import java.time.Year;
import java.util.function.IntSupplier;

public class Main {
    public static void main(String[] args) {

        IntSupplier currentYear =
            () -> Year.now().getValue();

        System.out.println(currentYear.getAsInt());
    }
}

2026

Explanation: The supplier retrieves and returns the current year using the Java Date-Time API.

Example: Java program to illustrate getAsInt method of IntSupplier Interface

import java.util.function.IntSupplier;

public class GFG {
    public static void main(String args[])
    {

        // Create a IntSupplier instance
        IntSupplier
            sup
            = () -> (int)(Math.random() * 10);

        // Get the int value
        // Using getAsInt() method
        System.out.println(sup.getAsInt());
    }
}

7

Explanation: In this example, an IntSupplier is created using a lambda expression that generates a random integer between 0 and 9. The getAsInt() method retrieves and returns the generated value, which is then printed on the screen. The output may vary each time the program runs.

Advantages of IntSupplier

• Avoids boxing and unboxing of Integer objects.
• Improves performance when working with primitive int values.
• Supports lambda expressions and method references.
• Useful for generating counters, random values, and calculations.
• Simplifies functional-style programming.
• Ideal for lazy evaluation and value generation.