Java Thread join merge result from two threads

class MyThread extends Thread {
   int[] a;/*from w ww  .ja  v a 2s .  c  o m*/

   MyThread(int[] ar) {
      a = ar;
      start();
   }

   public void run() {
      java.util.Arrays.sort(a);
   }
}

public class Main {
   public static void main(String args[]) throws Exception {
      int a[] = { 2, 3, 4, 0, 1 }, b[] = { 6, 9, 8, 7, 5 };
      MyThread t1 = new MyThread(a);
      MyThread t2 = new MyThread(b);
      t1.join();
      t2.join();
      int result[] = merge(a, b);
      for (int i = 0; i < result.length; i++)
         System.out.print(result[i] + " ");
   }

   static int[] merge(int[] a, int[] b) {
      int i = 0, j = 0, k = 0;
      int[] result = new int[a.length + b.length];
      while (i < a.length && j < b.length) {
         if (a[i] < b[j])
            result[k++] = a[i++];
         else
            result[k++] = b[j++];
      }
      while (i < a.length)
         result[k++] = a[i++];
      while (j < b.length)
         result[k++] = b[j++];
      return result;
   }
}