Using Java api, how to find out the memo attached to a payment operation?

Question

I can use the following code from example to receive payment event from public horizon. But the pos variable doesn't have memo information. Where should I get the memo from a certain paymente operation response?

paymentsRequest.stream(new EventListener<OperationResponse>() {
    @Override   public void onEvent(OperationResponse payment) {
    // Record the paging token so we can start from here next time.
    savePagingToken(payment.getPagingToken());

Answer 1

Memo can only be attached to a transaction, not operation. So you should rather listen to transactions stream or load a corresponding transaction by hash once a payment received.

The first option is better because transaction response contains XDR from which all related operations can be deserialized, while the second variant requires additional horizon requests.