Java Scanner nextBoolean() Method

The nextBoolean() is a method of Java Scanner class which is used to scan the next token of the input into a boolean value and returns that value. If the translation is successful, the scanner past the input that matched.

Syntax

Following is the declaration of nextBoolean() method:

Parameter

This method does not accept any parameter.

Returns

The nextBoolean() method returns the boolean scanned from the input.

Exceptions

InputMismatchException- It will thrown this Exception if the next token is not a valid boolean.

NoSuchElementException- It will thrown this Exception if the input is exhausted.

IllegalStateException- It will thrown this Exception if the innvocation is done after Scanner is closed.

Compatibility Version

Java 1.5 and above

Example 1

import java.util.*;
public class ScannerNextBooleanExample1 {  
	public static void main(String[] args) {       
           System.out.print("Are you above 18?- ");
           Scanner sc = new Scanner(System.in);
           boolean bn = sc.nextBoolean();
           if (bn == true) {
               System.out.println("You are over 18");
           } else if (bn == false) {
               System.out.println("You are under 18");
           }
           sc.close();          	      
	 }
}

Output:

Are you above 18?- True
You are over 18
Are you above 18?- False
You are under 18

Example 2

import java.util.*;  
public class ScannerNextBooleanExample2 {  
     public static void main(String args[]){ 
    	   String str = "Hello true World! 12 false 15 ";
         Float f = 2.123f;
         str = str + f;
         //Create a new scanner with string Object
         Scanner scanner = new Scanner(str);
         //Use US locale to be able to identify boolean in the string
         scanner.useLocale(Locale.US);
         //Find the next boolean token and print it
         while (scanner.hasNext()) {
            //Check if the next is a boolean, print found
            if (scanner.hasNextBoolean()) {
               System.out.println("Found Boolean:" + scanner.nextBoolean());
            }
            //If boolean is not found, print "Not Found"
            System.out.println("Not Found Boolean:" + scanner.next());
         }    
         scanner.close();
     }  
} 

Output:

Not Found Boolean:Hello
Found Boolean:true
Not Found Boolean:World!
Not Found Boolean:12
Found Boolean:false
Not Found Boolean:15
Not Found Boolean:2.123

Example 3

import java.util.*;  
public class ScannerNextBooleanExample3 {  
     public static void main(String args[]){ 
    	 System.out.print("Would you like to play? : ");
    	 Scanner scan = new Scanner(System.in);
    	 if(scan.nextBoolean()==true) {
    		System.out.println("Great! This will be fun.");
    	 }else {
    		System.out.println("Maybe next time");
    	 }
    	 scan.close();
     }  
} 

Output:

Would you like to play? : True
Great! This will be fun.

Would you like to play? : False
Maybe next time

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