Scanner hasNextBoolean() in Java

hasNextBoolean(): This method is available in java.util.Scanner class of Java.

Syntax:

boolean java.util.Scanner.hasNextBoolean()

This method returns true if the next token in this scanner's input can be interpreted as a boolean value using a case insensitive pattern created from the string "true|false".

Parameters: NA

Returns: true if and only if this scanner's next token is a valid boolean value.

Throws:

IllegalStateException - if this scanner is closed

Approach 1: When no exception

Java

import java.util.Scanner;

public class ScannerhasNextBoolean {
    public static void main(String[] args) {

        String source = "true false";
        Scanner scanner = new Scanner(source);

        System.out.println(scanner.hasNextBoolean());

        scanner.close();
    }
}

Output:

true

Approach 2: IllegalStateException 

Java

import java.util.Scanner;

public class ScannerhasNextBoolean {
    public static void main(String[] args) {

        String source = "true false";
        Scanner scanner = new Scanner(source);

        scanner.close();
        System.out.println(scanner.hasNextBoolean());

    }
}

Output:

Exception in thread "main" java.lang.IllegalStateException: Scanner closed
	at java.base/java.util.Scanner.ensureOpen(Scanner.java:1150)
	at java.base/java.util.Scanner.hasNext(Scanner.java:1540)
	at java.base/java.util.Scanner.hasNextBoolean(Scanner.java:1876)