Inbound messages, arriving at the channel adapter or gateway, are converted to the spring-messaging Message<?> payload using a message converter. By default, a SimpleMessageConverter is used, which handles java serialization and text. Headers are mapped using the DefaultHeaderMapper.inboundMapper() by default. If a conversion error occurs, and there is no error channel defined, the exception is thrown to the container and handled by the listener container’s error handler. The default error handler treats conversion errors as fatal and the message will be rejected (and routed to a dead-letter exchange, if the queue is so configured). If an error channel is defined, the ErrorMessage payload is a ListenerExecutionFailedException with properties failedMessage (the Spring AMQP message that could not be converted) and the cause. If the container AcknowledgeMode is AUTO (the default) and the error flow consumes the error without throwing an exception, the original message will be acknowledged. If the error flow throws an exception, the exception type, in conjunction with the container’s error handler, will determine whether the message is requeued. If the container is configured with AcknowledgeMode.MANUAL, the payload is a ManualAckListenerExecutionFailedException with additional properties channel and deliveryTag. This enables the error flow to call basicAck or basicNack (or basicReject) for the message, to control its disposition.spring-doc.cn