[jdom-interest] ConcurrentModificationException - why?

[Robert Koberg]

Hi,

The code below causes a ConcurrentModificationException. I don't see how the
iterators are overlapping. Can somebody see my error or tell me how I can
replace a list of elements?

Thanks for any advice,
-Rob

            -oOo-

private void updateFocusedItemColumns(HttpServletRequest req, LsbProject proj,
HttpSession http_session) {
  try {
    Element change = getChangeElement(req.getParameter("xml_out"));
    Element config = getSiteConfigElement(proj);
    Element elem = getFocusElem(req.getParameter("lsb_focus"), config);
    removeColumns(elem);
    addColumns(elem, change);
  } catch (IOException ioe) {
    error stuff...
  }
}

private Element getFocusElem(String focus_id, Element orig) {
  List children = orig.getChildren();
  for (Iterator i = children.iterator(); i.hasNext();) {
    Element elem = (Element)i.next();
    String id = elem.getAttributeValue("id");
    if (focus_id.equals(id)) {
      return elem;
    } else if (elem.hasChildren()) {
      Element _elem = getFocusElem(focus_id, elem);
      if (_elem!=null) return _elem;
    }
  }
  return null;
}

private void removeColumns(Element elem) {
  List cols = elem.getChildren("col");
  for (Iterator i = cols.iterator(); i.hasNext();) {
    Element col = (Element)i.next();
    elem.removeContent(col);
  }
}

private void addColumns(Element elem, Element add_elem) {
  List new_cols = add_elem.getChildren("col");
  for (Iterator i = new_cols.iterator(); i.hasNext();) {
    Element col = (Element)i.next();
    elem.addContent(col);
  }
}