output: #fixed code
                                  public void renameClass(Map classnames) {
          LongVector v = items;
          int size = numOfItems;
          classes = new HashMap(classes.size() * 2);
          for (int i = 1; i < size; ++i) {
              ConstInfo ci = (ConstInfo)v.elementAt(i);
              ci.renameClass(this, classnames);
              ci.makeHashtable(this);
          }
      }
input: #vulnerable code 
                                  public void renameClass(Map classnames) {
          LongVector v = items;
          int size = numOfItems;
          for (int i = 1; i < size; ++i)
              ((ConstInfo)v.elementAt(i)).renameClass(this, classnames);
      } 
                              #location 5 
                              #vulnerability type NULL_DEREFERENCE