code: public final int indexOf(Object elem, int index)
    {
  
      for (int i = index; i < m_firstFree; i++)
      {
        if (m_map[i] == elem)
          return i;
      }
  
      return java.lang.Integer.MIN_VALUE;
    }
docs: Searches for the first occurence of the given argument,
  beginning the search at index, and testing for equality
  using the equals method.
  
  @param elem object to look for
  @param index Index of where to begin search
  @return the index of the first occurrence of the object
  argument in this vector at position index or later in the
  vector; returns -1 if the object is not found.