code: public static CmsXmlContainerPage createDocument(CmsObject cms, Locale locale, String modelUri)
      throws CmsException {
  
          // create the XML content
          CmsXmlContainerPage content = new CmsXmlContainerPage(cms, locale, modelUri);
          // call prepare for use content handler and return the result
          return (CmsXmlContainerPage)content.getHandler().prepareForUse(cms, content);
      }
docs: Create a new instance of an container page based on the given default content,
  that will have all language nodes of the default content and ensures the presence of the given locale.<p>
  
  The given encoding is used when marshalling the XML again later.<p>
  
  @param cms the current users OpenCms content
  @param locale the locale to generate the default content for
  @param modelUri the absolute path to the container page file acting as model
  
  @throws CmsException in case the model file is not found or not valid
  
  @return the created container page