docs: @Override
      public synchronized void close() {
          if (isClosed()) {
              return;
          }
  
          // Close connection
          if (this.db != null) {
              try {
                  this.db.close();
              } catch (Exception e) {
                  LOGGER.log(Level.SEVERE, e.getMessage(), e);
              }
          }
  
          this.poiFile = null;
      }