选择排序算法的JAVA实现

package Utils.Sort;
/**
*利用选择排序法对数组排序，数组中元素必须实现了Comparable接口。
*/
public class ChooseSort implements SortStrategy
{
       /**
       *对数组obj中的元素以选择排序算法进行排序
       */
       public void sort(Comparable[] obj)
       {
              if (obj == null)
              {
                     throw new NullPointerException("The argument can not be null!");
              }
 
              Comparable tmp = null;
              int index = 0;
              for (int i = 0 ;i < obj.length - 1 ;i++ )
              {
                     index = i;
                     tmp = obj[i];
 
                     for (int j = i + 1 ;j < obj.length ;j++ )
                     {
                        &n