The **`Math.round()` method** in Java is used to round a number to its​ closest integer. This is done by adding $1/2$ to the number, taking the *floor* of the result, and casting the result to an integer data type.

Some of the edge cases of the `Math.round()` method are:
- If the argument is *NaN* (not a number), then the function will return $0$.
- If the argument is negative infinity or any value less than or equal to the value of `Integer.MIN_VALUE`, then the function returns `Integer.MIN_VALUE`.
- If the argument is positive infinity or any value greater than or equal to the value of `Integer.MAX_VALUE`, then the function returns `Integer.MAX_VALUE`.

Let's see the implementation of the `Math.round( )` method:





import java.lang.Math; // Needed to use Math.round()

class Program {
    public static void main( String args[] ) {
        double num1 = 74.65;
        System.out.println(Math.round(num1));
    }
}

import java.lang.Math; // Needed to use Math.round()

class Program {
    public static void main( String args[] ) {
        double num1 = -4.3;
        System.out.println(Math.round(num1));
    }
}

import java.lang.Math; // Needed to use Math.round()

class Program {
    public static void main( String args[] ) {
        double num1 = -13.56934;
        System.out.println(Math.round(num1 * 100.0) / 100.0); // Round to two decimal places
    }
}

How to use the Java Math.round() method

The Math.round() method in Java is used to round a number to its​ closest integer. This is done by adding 1/21/21/2 to the number, taking the floor of the result, and casting the result to an integer data type. 

How to use the Java Math.round() method

Basic use

Negative numbers

Specific decimal places