HOWTO · Java

The abs() Method in Java

This tutorial educates about how to use the abs() method using different code examples in Java.

By Mehvish AshiqPublished 2022-04-01Updated 2023-10-12
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We will learn about the abs() method in Java to find the absolute value of a specified number. We will be learning by writing and practicing various code examples.

What Is the Absolute Value in Java

Absolute value means a non-negative value of the specified number. For instance, the absolute value of -4 is 4.

We use the abs() method of the java.lang.Math package. It takes only one argument of type int, double, float, or long and returns its non-negative (absolute) value.

The following are some rules of thumb that you must remember to be an expert while finding an absolute value of a given number.

  1. If the argument’s data type is float or double:
    1.1 The abs() returns the positive value; it does not matter if the passed argument is positive or negative.
    1.2 It results as POSITIVE_INFINITY if we pass Infinity as an argument.
    1.3 It returns NaN if its argument is NaN.
    1.4 It returns a positive zero if the abs() method gets a negative or positive zero.
  2. If the argument’s data type is long or int:
    2.1 If the value of Long.MIN_VALUE or Integer.MIN_VALUE is equal to the abs() method’s argument, the output would be the same, a negative value.

Use the abs() Method to Find the Absolute Value of a Number in Java

In this section, we will be writing different code examples to practice all the rules that are given above.

Example Code (when a negative number is passed as an argument):

import java.lang.Math;

public class findAbsoluteValue {
  public static void main(String[] args) {
    int intNumber = -8;
    System.out.println("Before applying the Math.abs() function: " + intNumber);

    int absoluteValue = Math.abs(intNumber);
    System.out.println("After applying the Math.abs() function: " + absoluteValue);
  }
}

Output:

Before applying the Math.abs() function: -8
After applying the Math.abs() function: 8

Inside the main method, we declare and initialize a variable to hold a value further passed to the Math.abs() function to calculate a given number’s absolute value (positive value).

We print the value of a number before and after applying the Math.abs() function. This same process will be followed in the upcoming examples, but the variable name and type will be changed.

Example Code (when a positive number is passed as an argument):

import java.lang.Math;

public class findAbsoluteValue {
  public static void main(String[] args) {
    int intNumber = 8;
    System.out.println("Before applying the Math.abs() function: " + intNumber);

    int absoluteValue = Math.abs(intNumber);
    System.out.println("After applying the Math.abs() function: " + absoluteValue);
  }
}

Output:

Before applying the Math.abs() function: 8
After applying the Math.abs() function: 8

Example Code (when infinity is passed as an argument):

import java.lang.Math;

public class findAbsoluteValue {
  public static void main(String[] args) {
    double doubleNumber = Double.POSITIVE_INFINITY;
    System.out.println("Before applying the Math.abs() function: " + doubleNumber);

    double absoluteValue = Math.abs(doubleNumber);
    System.out.println("After applying the Math.abs() function: " + absoluteValue);
  }
}

Output:

Before applying the Math.abs() function: Infinity
After applying the Math.abs() function: Infinity

Example Code (when NaN is passed as an argument):

import java.lang.Math;

public class findAbsoluteValue {
  public static void main(String[] args) {
    double doubleNumber = Double.NaN;
    System.out.println("Before applying the Math.abs() function: " + doubleNumber);

    double absoluteValue = Math.abs(doubleNumber);
    System.out.println("After applying the Math.abs() function: " + absoluteValue);
  }
}

Output:

Before applying the Math.abs() function: NaN
After applying the Math.abs() function: NaN

Example Code (when positive zero or negative zero is passed as an argument):

import java.lang.Math;

public class findAbsoluteValue {
  public static void main(String[] args) {
    int number, absoluteValue;

    number = -0;
    System.out.println("Before applying the Math.abs() function: " + number);
    absoluteValue = Math.abs(number);
    System.out.println("After applying the Math.abs() function: " + absoluteValue);

    number = 0;
    System.out.println("Before applying the Math.abs() function: " + number);
    absoluteValue = Math.abs(number);
    System.out.println("After applying the Math.abs() function: " + absoluteValue);
  }
}

Output:

Before applying the Math.abs() function: 0
After applying the Math.abs() function: 0
Before applying the Math.abs() function: 0
After applying the Math.abs() function: 0

Example Code (when Long.MIN_VALUE or Integer.MIN_VALUE is passed as an argument):

import java.lang.Math;

public class findAbsoluteValue {
  public static void main(String[] args) {
    long longNumber = Long.MIN_VALUE;
    System.out.println("Before applying the Math.abs() function: " + longNumber);
    long longAbsVal = Math.abs(longNumber);
    System.out.println("After applying the Math.abs() function: " + longAbsVal);

    int intNumber = Integer.MIN_VALUE;
    System.out.println("Before applying the Math.abs() function: " + intNumber);
    int intAbsVal = Math.abs(intNumber);
    System.out.println("After applying the Math.abs() function: " + intAbsVal);
  }
}

Output:

Before applying the Math.abs() function: -9223372036854775808
After applying the Math.abs() function: -9223372036854775808
Before applying the Math.abs() function: -2147483648
After applying the Math.abs() function: -2147483648

About the author

Mehvish Ashiq

Mehvish Ashiq is a former Java Programmer and a Data Science enthusiast who leverages her expertise to help others to learn and grow by creating interesting, useful, and reader-friendly content in Computer Programming, Data Science, and Technology.

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