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 !!