code: protected Format getFormat(Map<String,String> metaInfo) {
          Format format = Format.json;
          metaInfo.put(Listener.METAINFO_CONTENT_TYPE, Listener.CONTENT_TYPE_JSON);
          String formatParam = (String) metaInfo.get("format");
          if (formatParam != null) {
              if (formatParam.equals("xml")) {
                  format = Format.xml;
                  metaInfo.put(Listener.METAINFO_CONTENT_TYPE, Listener.CONTENT_TYPE_XML);
              }
              else if (formatParam.equals("text")) {
                  format = Format.text;
                  metaInfo.put(Listener.METAINFO_CONTENT_TYPE, Listener.CONTENT_TYPE_TEXT);
              }
          }
          else {
              if (Listener.CONTENT_TYPE_XML.equals(metaInfo.get(Listener.METAINFO_CONTENT_TYPE)) || Listener.CONTENT_TYPE_XML.equals(metaInfo.get(Listener.METAINFO_CONTENT_TYPE.toLowerCase()))) {
                  format = Format.xml;
                  metaInfo.put(Listener.METAINFO_CONTENT_TYPE, Listener.CONTENT_TYPE_XML);
              }
              else if (Listener.CONTENT_TYPE_TEXT.equals(metaInfo.get(Listener.METAINFO_CONTENT_TYPE)) || Listener.CONTENT_TYPE_TEXT.equals(metaInfo.get(Listener.METAINFO_CONTENT_TYPE.toLowerCase()))) {
                  format = Format.text;
                  metaInfo.put(Listener.METAINFO_CONTENT_TYPE, Listener.CONTENT_TYPE_JSON);
              }
          }
          return format;
      }
docs: Default format is now JSON.