code: private String readUid(File uidFile) {
          String uid = null;
  
          // Try to read the shared UID
          try (BufferedReader br = new BufferedReader(new FileReader(uidFile))) {
              String line;
  
              while ((line = br.readLine()) != null) {
                  uid = line;
              }
          } catch (IOException ioe) {
          }
  
          return uid;
      }
docs: Read a UID file
  
  @param uidFile The UID file to read
  @return The UID read