isEmpty(); and isBlank();

 package com.company;

public class Main {

    public static void main(String[] args) {
        String a = " ";
        System.out.println(a.isEmpty());
        System.out.println(a.isBlank());
        String b = "";
        System.out.println(b.isEmpty());
        System.out.println(b.isBlank());
    }
}

Outcome:

false

true

true

true

a - is not empty despite the fact that there is a space inside it. Any character inside string

means it is not empty. 

a - is blank, because it does not have any character and has only space inside it.

b - is empty, because it does not have any character. That is why it is true.

b - is blank, because it does not have any character.