1 PRivate int hash; // Default to 0 2 public int hashCode() { 3         int h = hash; 4         if (h == 0 && value.length > 0) { 5             char val[] = value; 6             for (int i = 0; i < value.length; i++) { 7                 h = 31 * h + val[i]; 8             } 9             hash = h;10         }11         return h;12 }