code: public int checkIn() {
  
          try {
              synchronized (STATIC_LOCK) {
                  m_logStream = new PrintStream(new FileOutputStream(DEFAULT_LOGFILE_PATH, false));
                  CmsObject cms = getCmsObject();
                  if (cms != null) {
                      return checkInInternal();
                  } else {
                      m_logStream.println("No CmsObject given. Did you call init() first?");
                      return -1;
                  }
              }
          } catch (FileNotFoundException e) {
              e.printStackTrace();
              return -2;
          }
      }
docs: Start export and check in of the selected modules.
  @return The exit code of the check in procedure (like a script's exit code).