code: private void createPool(String poolName, Properties connectionPoolProperties) {
  
      releaseConnectionPool(poolName);
  
      // DBUtils execute methods require autoCommit to be true.
      connectionPoolProperties.put("autoCommit", true);
  
      HikariConfig config = new HikariConfig(connectionPoolProperties);
      config.setPoolName(poolName);
      HikariDataSource ds = new HikariDataSource(config);
      pools.put(poolName, ds);
      logger.info("Initialized pool '{}'", poolName);
    }
docs: Creates a Hikari connection pool and puts it in the pools map.
  
  @param poolName
  @param connectionPoolProperties