code: public static CmsXmlGroupContainer unmarshal(
          CmsObject cms,
          String xmlData,
          String encoding,
          EntityResolver resolver) throws CmsXmlException {
  
          // create the XML content object from the provided String
          return unmarshal(cms, CmsXmlUtils.unmarshalHelper(xmlData, resolver), encoding, resolver);
      }
docs: Factory method to unmarshal (generate) a group container instance from a String
  that contains XML data.<p>
  
  The given encoding is used when marshalling the XML again later.<p>
  
  <b>Warning:</b><br/>
  This method does not support requested historic versions, it always loads the
  most recent version. Use <code>{@link #unmarshal(CmsObject, CmsResource, ServletRequest)}</code>
  for history support.<p>
  
  @param cms the cms context, if <code>null</code> no link validation is performed
  @param xmlData the XML data in a String
  @param encoding the encoding to use when marshalling the group container later
  @param resolver the XML entity resolver to use
  
  @return a group container instance unmarshalled from the String
  
  @throws CmsXmlException if something goes wrong