How to Handle Integer Overflow and Underflow in Java

1. Overview of Integer Overflow and Underflow in Java
2. Integer Overflow in Java
3. Integer Underflow in Java

This article describes the overflow and underflow of an integer data type and the handling of this problem.

Overview of Integer Overflow and Underflow in Java

You may face an overflow or underflow error if you work with integer values. It happens when we declare a variable wrongly, like assigning a value that is out of range for the declared data type.

As we know, there are four levels of integer data types containing different sizes that are given below:

If we consider the int in Java, it has a range of values that we can assign. As we already know, that int data type is 32-bits in size; so, the range of accepted values in int is between -2147483648 to 2147483647.

You can quickly get the maximum and minimum value by using Integer.MAX_VALUE and Integer.MIN_VALUE.

Integer Overflow in Java

Here, we will see the occurrence of Integer overflow and its handling.

Occurrence of Integer Overflow

Example Code:

public class IntegerOverflow {
  public static void main(String[] args) {
    int Intvalue = Integer.MAX_VALUE - 1;
    for (int i = 0; i < 4; i++) {
      System.out.println(Intvalue);
      Intvalue = Math.addExact(Intvalue, 1);
    }
  }
}

Now when you execute the above program, the console will show your the below output:

2147483646
2147483647
Exception in thread "main" java.lang.ArithmeticException: integer overflow
    at java.base/java.lang.Math.addExact(Math.java:828)at IntegerOverflow.main(IntegerOverflow.java:9)

Handle Integer Overflow

We need to increase the value range to solve our example above. In our case, we typecast the integer to long. Our updated code for the above example will be as follows.

Example Code:

public class IntegerOverflow {
  public static void main(String[] args) {
    int Intvalue = Integer.MAX_VALUE - 1;
    long NewValue = (long) Intvalue; // Upgrading to new type
    for (int i = 0; i < 4; i++) {
      System.out.println(NewValue);
      NewValue = Math.addExact(NewValue, 1);
    }
  }
}

Now you will see the below output in your console.

2147483646
2147483647
2147483648
2147483649

Integer Underflow in Java

In this section, we will learn about Integer underflow in Java and how we can handle it.

Occurrence of Integer Underflow

Example Code:

public class IntegerUnderflow {
  public static void main(String[] args) {
    int value = -2147483699; // Creating underflow intentionally
    System.out.println(value - 1);
  }
}

Now when you execute the above program, the console will show your the below output:

/IntegerUnderflow.java:3: error: integer number too large
    int value = -2147483699; // Creating underflow intentionally
                 ^
1 error

Handle Integer Underflow

To solve the error above, we need to increase the range of the value again, and to do that, we can typecast the integer value to the next level. Have a look at the code shared below.

Example Code:

public class IntegerUnderflow {
  public static void main(String[] args) {
    long value = (long) -2147483638; // Type Casting
    System.out.println(value - 1);
  }
}

Now you will see the below output in your console.

-2147483639

So, we need to increase the range to the data type in case of solving the overflow or underflow problems.