code: static void attach(String dbName, Connection connection, String extraInfo) {
          if(ConnectionsAccess.getConnectionMap().get(dbName) != null){
              throw new InternalException("You are opening a connection " + dbName + " without closing a previous one. Check your logic. Connection still remains on thread: " + ConnectionsAccess.getConnectionMap().get(dbName));
          }
          ConnectionsAccess.getConnectionMap().put(dbName, connection);
          LogFilter.log(LOGGER, LogLevel.DEBUG, "Attached connection named: {}: to current thread: {}. Extra info: {}", dbName, connection, extraInfo);
      }
docs: Attaches a connection to a ThreadLocal and binds it to a name.
  
  @param dbName
  @param connection