Swapping using a third variable in Java -

what need use third variable swap numbers? sorry, don't it.

here sample code have sorting elements of array based on length of each element. can see here, using third variable, , swapping elements of array. have different implementation program works, found below example online, , understand swapping useful for? if explain me, great.

public class stringsort {     public static void main(string[] args) {         string[] arr = new string[] { "abcd", "dexter", "stringsortexample", "fruit", "apple","car" };                       comparearrayelements(arr);                system.out.println("the strings in sorted order of length are: ");         (string sortedarray : arr) {             system.out.println(sortedarray);         }     }      public static void comparearrayelements(string[] arr) {         string temp = "";         (int = 0; < arr.length - 1; i++) {             (int j = i+1; j < arr.length; j++) {                 if (arr[i].length() > arr[j].length())                 {                     temp = arr[i];                     arr[i] = arr[j];                     arr[j] = temp;                 }             }         }            } } 

the short answer can't juggle in java!

think of each variable hand can "hold" 1 value; e.g. ball.

if have 2 hands , 2 balls, way switch balls opposite hands involves throwing 1 of balls in air (or that). there no "throw value air" operation in java.

if can't juggle need third hand (or other temporary holding place) swap balls. , in java terms, means temporary variable.

^{for record, found analogy useful when learning program. don't take far :-).}

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(in fact, if talking integers, there mathematical trick can use swap numbers ... involving xor ... doesn't work in general.)