Java Double isNaN() Method

Java isNaN() method is a part of the Double class of the java.lang package. This method is used to check whether the double value passed is Not-A-Number(NaN) or not. It returns the boolean value true for NaN values and false for non-NaN values.

Syntax:

public boolean isNaN()  

Parameters:

No parameter is passed in this method.

Returns:

Returns the boolean value true for NaN values and false for non-NaN values.

Example 1:

Here, the equivalent values are returned in accordance with the double value passed as an argument.

import java.lang.Double;
public class StudyTonight
{  
    public static void main(String[] args) 
    {  
        Double d1 = 67.78;  
        Double d2 = 0.0; 
        Double d3 = -d1/0.0;
        Double d4 = d2/0.0;
        Double d5 = 0.0/0.0;      
           
        System.out.println("The value is : " +d1.isNaN()); //returns false for finite value  
        System.out.println("The value is : " +d2.isNaN()); //returns false for infinite value 
        System.out.println("The value is : " +d3.isNaN()); //returns false for infinaite value 
        System.out.println("The value is : " +d4.isNaN()); // returns true for NaN value
        System.out.println("The value is : " +d5.isNaN()); // returs true for NaN 
      
    }  
}  

The value is : false
The value is : false
The value is : false
The value is : true
The value is : true

Example 2:

Here is a user-defined example where anyone using this code can put a value of his choice and get the equivalent output.

import java.lang.Double;
import java.util.Scanner;

public class StudyTonight
{  
    public static void main(String[] args) 
    {  
        try
        {
           System.out.println("Enter the value");
           Scanner sc = new Scanner(System.in);
           double i = sc.nextDouble();
           Double d = i;
          
           boolean b = d.isNaN();
           if(b== true)
           {
             System.out.println("Value is NaN");
           }
           else
           {
             System.out.println("Value is non NaN");
           }
         }         
         catch(Exception e)
         {
           System.out.println("Invalid Input");
         }   
    } 
}  

Enter the value
NaN
Value is NaN
******************
Enter the value
90.678
Value is non NaN
******************
Enter the value
0x567
Invalid Input

Live Example:

Here, you can test the live code example. You can execute the example for different values, even can edit and write your examples to test the Java code.