20.10.1. About Duplicate Message Detection
Duplicate message detection allows filtering of duplicate messages without the need of coding the duplicate detection logic within the application. You can configure duplicate message detection in HornetQ.
When a sender(client/server) sends a message to another server there can be a situation where the target server(receiver) or the connection fails after sending the message but before sending a response to the sender indicating that the process was successful. In such situations, it is very difficult for the sender(client) to determine if the message was sent successfully to the intended receiver.
The message send may or may not be successful depending on when the target receiver or connection failed (before or after sending the message). If the sender (client/server) decides to resend the last message it can result in a duplicate message being sent to the address.
HornetQ provides duplicate message detection for messages sent to addresses.