code: private void updateConfig() {
          // JDBC URL
          final String u = this.model.getUrl();
          final String url = (u != null) ? u.trim() : null;
  
          if (url == null || url.length() == 0) {
              this.conf.remove("jdbc.url");
          } else {
              this.conf.put("jdbc.url", url);
          } // end of else
  
          // DB user name
          final String n = this.model.getUser();
          final String user = (n != null) ? n.trim() : null;
  
          if (user == null || user.length() == 0) {
              this.conf.remove("db.user");
          } else {
              this.conf.put("db.user", user);
          } // end of else
  
          // DB charset
          final Charset charset = this.model.getCharset();
  
          if (charset == null) {
              this.conf.remove("db.charset");
          } else {
              this.conf.put("db.charset", charset.name());
          } // end of else
  
          // Persist configuration
          try {
              this.saveConf.call();
          } catch (Exception e) {
              e.printStackTrace();
          } // end of catch
      }
docs: Updates application configuration.