Class MqttConnectionLostException

java.lang.Object
java.lang.Throwable
java.lang.Exception
java.lang.RuntimeException
org.mqtt4j.hato.MqttException
org.mqtt4j.hato.MqttConnectionLostException
All Implemented Interfaces:
Serializable
public final class MqttConnectionLostException extends MqttException

A connection ended before an operation's outcome could be confirmed. This includes an unacknowledged publication, whose outcome is unknown even if its exchange is later discarded. In a persistent session, QoS 1 and QoS 2 exchanges survive connection termination in the same client, and their futures wait instead of failing while the client reconnects automatically. The next connection reports ConnAck.sessionPresent() true when those exchanges resume, or false when they are discarded without replay, which fails the waiting futures with this exception. Previously failed futures remain failed; neither Session Present value proves that a publication was never received. Closing the client discards its local exchanges.

Subscription registrations and removals survive connection termination: their observations do not fail when a connection ends, and PullSubscription.receive() keeps waiting. Subscription.established(), Subscription.unsubscribe(), and pull receives report this exception only when an internal failure closes the client, carrying that failure as its cause. Locally detected packet failures carry MqttProtocolException as their cause, and a DISCONNECT from an MQTT 5.0 broker carries MqttBrokerDisconnectException.

See Also:

  • Constructor Details

    • MqttConnectionLostException

      public MqttConnectionLostException()
      A loss without a cause.

    • MqttConnectionLostException

      public MqttConnectionLostException(Throwable cause)
      A loss with the failure that caused it.
      Parameters:
      cause - the failure that caused the loss