code: public H2DataSource init() throws Exception {
          if (dbMode == DBMode.LOCAL) {
              String port = getPort();
  
              if (port.isEmpty()) {
                  server = Server.createTcpServer();
              } else {
                  server = Server.createTcpServer("-tcpPort", port);
              }
  
              server.start();
          }
  
          return this;
      }
docs: If running H2 in local mode, starts the server.
  
  @return this (for chaining)
  @throws Exception Unspecified exception