Java Program to Check if a String is Empty or Null

In this java program, we will learn about how to check whether a string is empty or null. Below is a demonstration of the same:

Input String : null 
Output: True

Input String : "ABCD" 
Output: False

Input String : "" 
Output: True

We consider a string to be empty if it's either null or a string without any length. If a string only consists of whitespace, then we call it blank.

To understand this java program, you should have understanding of the following Java programming concepts:

Java Program to Check if a String is Empty or Null

public class NullEmptyStringCheck {

  static String isNullOrEmptyString(String str) {
    if (str == null) {
      return "Null String";
    } else if(str.isEmpty()){
      return "Empty String";
    } else {
      return "Neither Empty nor Null String";
  public static void main(String[] args) {
    String str1 = null;
    String str2 = "";
    String str3 = "ABCD";

    System.out.println("str1 is " + isNullOrEmptyString(str1));
    System.out.println("str2 is " + isNullOrEmptyString(str2));
    System.out.println("str3 is " + isNullOrEmptyString(str3));
str1 is Null String
str2 is Empty String
str3 is Neither Empty nor Null String