@Override
  public void characters(char[] ch, int start, int length) throws SAXException {

    Object top = stack.peek();

    StringBuilder sb;
    if (top instanceof StringBuilder) {
      sb = (StringBuilder) top;

    } else {
      sb = new StringBuilder();
      stack.push(sb);
    }

    sb.append(ch, start, length);
  }
Long strings in XML files may generate multiple <code>characters</code> callbacks. Coalesce
multiple callbacks into one big string by using a <code>StringBuilder</code>. See bug 32122.
geode-core/src/main/java/org/apache/geode/admin/internal/ManagedEntityConfigXmlParser.java