java - unable to get proper result using threads -

suppose have 3 arrays different length. want sort these 3 arrays 3 different threads.

i wrote below code this. write or there happening wrong. giving me correct result , values of arrays merging other array's values:

i added syncronized display method, again getting incorrect result.

public class threaddemo implements runnable {     private int[] arr;     private string[] s_arr;      public threaddemo(int arr[]) {         this.arr=arr;     }     @override     public void run() {         getsorted(arr);         try{             thread.sleep(2000);         }catch(interruptedexception e){             e.printstacktrace();         }     }      private void getsorted(int[] arr) {          (int = 0; < arr.length; i++) {             (int j = 0; j < (arr.length-1) - i; j++) {                 if (arr[j] > arr[j + 1]) {                     int temp = arr[j];                     arr[j] = arr[j + 1];                     arr[j + 1] = temp;                 }             }         }          display(arr);     }  public static void display(int[] a){          for(int i:a)             system.out.print(i+" ");         system.out.println();      }     public static void main(string[] args) {         int arr1[]={8,25,9,12,13,17,1};         int arr2[]={38,2,19,12,3,17,16};         int arr3[]={3,22,9,1,34,17,86};         threaddemo demo1=new threaddemo(arr1);         thread t1=new thread(demo1);         threaddemo demo2=new threaddemo(arr2);         thread t2=new thread(demo2);         threaddemo demo3=new threaddemo(arr3);         thread t3=new thread(demo3);         t1.start();         t2.start();         t3.start();     } } 

output #1: here values mixing.

1 8 9 12 13 17 25 2 3 12 16 17 1 3 9 17 22 34 86  19 38 

output #2: correct

1 8 9 12 13 17 25  2 3 12 16 17 19 38  1 3 9 17 22 34 86  

output #3: incorrect

1 8 9 12 13 17 25  2 1 3 3 12 9 16 17 17 22 19 38  34 86   public static synchronized void display(int[] a){          for(int i:a)             system.out.print(i+" ");         system.out.println();      } 

your arrays in correct order. printed results being interleaved because prints happening on different threads.

sort arrays on each thread , print results once threads have finished.