吸血鬼问题，求助，调试通过，运行的时候什么也没有 ~！
 求帮忙啊 ！！~
class Vampire2
{
    public boolean number(int sum)
    {
        int[] vam = new int[4];
        
        vam[0] = sum / 1000;
        
        vam[1] = ((sum - sum * 1000) / 100);
        
        vam[2] = ((sum - sum * 1000 - vam[1] * 100) / 10);
        
        vam[3] = (sum - sum * 1000 - vam[1] * 100 - vam[2] * 10);
        
        if(vam[2] == 0 && vam[3] == 0)
        {
            return false;
        }
                     
        for (int i = 0; i < 4; i++)
        {  
             for (int j = 0; j < 4; j++)
            {      
                for (int k = 0; k < 4; k++)
                {  
                    for (int l = 0; l < 4; l++)
                    {               
                           if (i != j && i != k && i != l && j != k && j != l && j != l && k != l)
                           {  
                               int n1 = vam[i] * 10 + vam[j];
                           
                               int n2 = vam[k] * 10 + vam[l];
                           
                            if(n1 * n2 == sum)
                            {
                                System.out.println(sum + " = " + n1 + " * " + n2);
                                return true;
                            }
                            }  
                     }  
                   }  
                }         
          }   
      return false;
     }   
  
  public static void main(String[] args)
  {
      Vampire2 vampire = new Vampire2();
      
      for(int num = 1000; num < 10000; num++)
      {
          vampire.number(num);
      }
  }   

}