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Java String isEmpty Example

  1. /*
  2.         Java String isEmpty Example.
  3.         This Java String isEmpty example shows how to check whether the given
  4.         string is empty or not using isEmpty method of Java String class.
  5.  */
  6. public class JavaStringIsEmptyExample {
  7.         public static void main(String args[]){
  8.                
  9.                 String str1 = "";
  10.                 String str2 = null;
  11.                 String str3 = "Hello World";
  12.                
  13.                 /*
  14.                  * To check whether the String is empty or not, use
  15.                  * boolean isEmpty() method of Java String class.
  16.                  *
  17.                  * This method returns true if and only if string.length() is 0.
  18.                  */
  19.                
  20.                 System.out.println("Is String 1 empty? :" + str1.isEmpty());
  21.                
  22.                 //this will throw NullPointerException since str2 is null
  23.                 //System.out.println("Is String 2 empty? :" + str2.isEmpty());
  24.                
  25.                 System.out.println("Is String 3 empty? :" + str3.isEmpty());
  26.                
  27.                 /*
  28.                  * Please note that isEmpty method was added in JDK 1.6 and it is not available
  29.                  * in previous versions.
  30.                  *
  31.                  * However, you can use  
  32.                  * (string.length() == 0) instead of (string.isEmpty())
  33.                  * in previous JDK versions.
  34.                  */
  35.         }
  36. }
  37.  
  38. /*
  39. Output of Java String isEmpty would be
  40. Is String 1 empty? :true
  41. Is String 3 empty? :false
  42. */