code: public void load() {
  
          try {
              File f = new File(persistFile.toString());
              if (f.exists()) {
                  // we have V4 config
                  loadVer4(persistFile.toString());
              } else {
                  String s1 = persistFile.toString().replace("3.xml", "2.xml");
                  f = new File(s1);
  
                  if (f.exists()) {
                      loadVer3(s1);
                      this.store();
                      f.delete();
                  } else {
                      s1 = persistFile.toString().replace("3.xml", ".xml");
                      f = new File(s1);
  
                      if (f.exists()) {
                          if (!loadVer1(s1)) {
                              loadVer2(s1);
                          }
                      }
  
                      this.store();
                      f.delete();
                  }
              }
  
  //            File f = new File(persistFile.toString());
  //            if (f.exists()) {
  //                // we have V3 config
  //                loadVer3(persistFile.toString());
  //            } else {
  //                String s1 = persistFile.toString().replace("2.xml", ".xml");
  //                f = new File(s1);
  //
  //                if (f.exists()) {
  //                    if (!loadVer1(s1)) {
  //                        loadVer2(s1);
  //                    }
  //                }
  //
  //                this.store();
  //                f.delete();
  //            }
          } catch (XMLStreamException ex) {
              ex.printStackTrace();
              logger.error(String.format("Failed to load the SS7 configuration file. \n%s", ex.getMessage()));
          } catch (FileNotFoundException e) {
              logger.warn(String.format("Failed to load the SS7 configuration file. \n%s", e.getMessage()));
          } catch (IOException e) {
              logger.error(String.format("Failed to load the SS7 configuration file. \n%s", e.getMessage()));
          }
      }
docs: Load and create LinkSets and Link from persisted file
  
  @throws Exception