How to pass integer by reference in Java

Last Updated : 11 Jul, 2025

Java is pass by value and it is not possible to pass integer by reference in Java directly. Objects created in Java are references which are passed by value. Thus it can be achieved by some methods which are as follows:

By creating Wrapper Class: As we know that Integer is an immutable class, so we wrap an integer value in a mutable object through this method. Approach:

Get the integer to be passed
Create an object of another class with this integer
Using wrapper class so as to wrap integer value in mutable object which can be changed or modified
Now whenever you need the integer, you have to get it through the object of the class
Hence the Integer has been passed by reference

Below is the implementation of the above approach: Example:

Java

// Java program to pass the integer by reference

class Test {
    public Integer value;

    Test(Integer value)
    {

        // Using wrapper class
        // so as to wrap integer value
        // in mutable object
        // which can be changed or modified
        this.value = value;
    }

    @Override
    public String toString()
    {
        return String.valueOf(value);
    }
}

class Main {
    public static void modification(Test x)
    {
        x.value = 1000;
    }

    public static void main(String[] args)
    {
        Test k = new Test(50);
        modification(k);

        // Modified value gets printed
        System.out.println(k);
    }
}

Output:

Wrapping primitive value using an array: This process of wrapping is done by using an array of length one. Approach:

Get the integer to be passed
This process of wrapping is done by using an array of length one.
Now whenever you need the integer, you have to get it through the object of the array
Hence the Integer has been passed by reference

Below is the implementation of the above approach: Example:

Java

// Java program to pass the integer by reference

class PassByReference {
    public static void increment(int[] array)
    {

        // increment in the actual value
        array[0]++;
    }

    public static void main(String[] args)
    {
        int k = 100;

        // wrapping is done
        // by using array of length one
        int[] array = { k };

        // Reference is passed
        increment(array);

        // incremented value printed
        System.out.println(array[0]);
    }
}

Output:

Using AtomicInteger: This is a built in Java class which provides a single threaded environment. Approach:

Get the integer to be passed
Create an AtomicInteger object by passing this integer as parameter to its constructor
Now whenever you need the integer, you have to get it through the object of the AtomicInteger
Hence the Integer has been passed by reference

Below is the implementation of the above approach: Example:

Java

// Java program to pass the integer by reference

import java.util.concurrent.atomic.AtomicInteger;

class PassByReference {
    public static void setvalue(AtomicInteger x)
    {

        // setting new value
        // thus changing the actual value
        x.set(1000);
    }

    public static void main(String[] args)
    {

        // provides single threaded environment
        AtomicInteger k = new AtomicInteger(50);

        // passed by reference
        setvalue(k);

        System.out.println(k);
    }
}

Output:

Using Apache MutableInt Class: We can use MutableInt class by importing the package from Commons Apache. Approach:

Get the integer to be passed
Create an MutableInt object by passing this integer as parameter to its constructor
Now whenever you need the integer, you have to get it through the object of the MutableInt
Hence the Integer has been passed by reference

Below is the implementation of the above approach: Example:

Java

// Java program to pass the integer by reference

import org.apache.commons.lang3.mutable.MutableInt;

class Main {
    public static void increment(MutableInt k)
    {
        k.increment();
    }

    public static void main(String[] args)
    {

        // Using Mutable Class whose object's fields
        // can be changed accordingly
        MutableInt k = new MutableInt(8);

        increment(k);
        System.out.println(k);
    }
}