code: public DataConnection getConnection() {
          DataConnection connection;
  
          for (connection = availableConnections.poll();
               connection != null && !connection.isUsable();
               connection = availableConnections.poll())
          {
              if (!connection.isUsable()) {
                  connection.close();
              }
          }
  
          if (connection == null) {
              connection = new DataConnection(getDataUri());
  
              try {
                  connection.connect();
              }
              catch (Exception e) {
                  logger.error("[getConnection] could not connect to database", e);
                  return null;
              }
          }
  
          connection.setLocale(threadLocale.getLocale());
  
          return connection;
      }
docs: Gets a connection from the pool of available and free data connections to this server.
  @return data connection to this server