String isBlank() – Check blank or empty string in Java

Learn to use String.isBlank() method to determine is a given string is blank or empty or contains only white spaces. isBlank() method has been added in Java 11.

To check is given string does not have even blank spaces, use String.isEmpty() method.

1. String isBlank() Method

This method returns true if the given string is empty or contains only white space code points, otherwise false.

It uses Character.isWhitespace(char) method to determine a white space character.

/**
* returns 	- true if the string is empty or contains only white space codepoints
*			- otherwise false
*/

public boolean isBlank()

2. String isBlank() example

Java program to check if given string is blank or not.

public class Main 
{
	public static void main(String[] args) 
	{
		System.out.println( "ABC".isBlank() );			//false

		System.out.println( " ABC ".isBlank() );		//false

		System.out.println( "  ".isBlank() );			//true

		System.out.println( "".isBlank() );				//true
	}
}

Program output.

false
false
true
true

3. isBlank() vs isEmpty()

Both methods are used to check for blank or empty strings in java. The difference between both methods is that isEmpty() method returns true if, and only if, string length is 0.

isBlank() method only checks for non-whitespace characters. It does not check the string length.

public class Main 
{
	public static void main(String[] args) 
	{
		System.out.println( "ABC".isBlank() );		//false
		System.out.println( "  ".isBlank() );		//true

		System.out.println( "ABC".isEmpty() );		//false
		System.out.println( "  ".isEmpty() );		//false
	}
}

Program output.

false
true
false
false

Happy Learning !!