ConnectionPool.handleException(Throwable err) always not work

[froggengoing]

Questions

i want to query some data from db use MySQLPoolImpl,process the data and then return to browser use vertx-web

however when i handler the result from querystatemnt , it throw nullpointexception by accident, and i think i will rerouter to the exceptionhandler which i define in Router. but the truth is it do nothing,let the brower has no response

Version

3.9.6

my code :

mySQLPool.preparedQuery(sql).execute(tuple, ar -> {
          int i = 1/0;
          if (ar.succeeded()) {
                  //do somthing
          } else {
                  //do somthing
          }
 });

and i debug to follow the stack to see how the vertx handler the exception ,i find out that：method(io.vertx.sqlclient.impl.ConnectionPool.PooledConnection#handleException) will always not to excute because the holder is always null.but i dont find the place to set holder.it's my carelessness or it 's a bug

 private class PooledConnection implements Connection, Connection.Holder  {

    @Override
    public void handleException(Throwable err) {
      if (holder != null) {
        holder.handleException(err);
      }
    }
}