Camel no error handler invoked on exception with multipleConsumer=true and POJO #Consume Annotation - spring

Question

I've been trying to figure out how route errors to my own error handler with the following, seemingly simple configuration, but Camel is swallowing the exception without routing it to any error handler I configure. I've run out of ideas. Any help would be much appreciated.
I've got a seda route that supports multiple consumers:
#Component
public class MessageGenerator {
public static final String ERROR_GENERATOR_CHANNEL = "seda:my-error-generator?multipleConsumers=true&concurrentConsumers=3";
private final FluentProducerTemplate producerTemplate;
public MessageGenerator(FluentProducerTemplate producerTemplate) {
this.producerTemplate = producerTemplate;
}
public void generateMessage() {
producerTemplate
.to(ERROR_GENERATOR_CHANNEL)
.withBody("Hello World")
.asyncSend();
}
}
I've got two separate POJO consumers:
#Configuration
public class MessageConsumer1 {
#Consume(ERROR_GENERATOR_CHANNEL)
void receiveMessage(String message) {
System.out.println("Received message 1: " + message);
throw new NullPointerException("Error generated");
}
}
#Configuration
public class MessageConsumer2 {
#Consume(ERROR_GENERATOR_CHANNEL)
void receiveMessage(String message) {
System.out.println("Received message 2: " + message);
}
}
When I run the following example, the NullPointerException gets swallowed by the underlying Camel MulticastProcessor as we can see in the logs:
Received message 2: Hello World
Received message 1: Hello World
2022-01-15 13:40:23.711 DEBUG 32945 --- [error-generator] o.a.camel.processor.MulticastProcessor : Message exchange has failed: Multicast processing failed for number 0 for exchange: Exchange[] Exception: java.lang.NullPointerException: Error generated
2022-01-15 13:40:23.711 DEBUG 32945 --- [error-generator] o.a.camel.processor.MulticastProcessor : Message exchange has failed: Multicast processing failed for number 0 for exchange: Exchange[] Exception: java.lang.NullPointerException: Error generated
The exception only gets logged as debug and never gets propagated to any error handler I set up.
Any thoughts on how I could receive the error in my own error handler rather than Camel swallowing the exception as a debug statement?
Note1: I've attempted many variations on both default error handling and default dead letter handling to no avail. I could just be doing it wrong...
Note2: that I'm using Spring[Boot] here too, hence the #Configuration annotation.

Answer 1

Note1: I've attempted many variations on both default error handling and default dead letter handling to no avail. I could just be doing it wrong...
Haven't used #Consume annotations but generally if you want Camel route not to handle any errors you can use .errorHandler(noErrorHandler()). This can be used to pass the error back to parent route or all the way to the code calling ProducerTemplate.sendBody.
Example:
public class ExampleTest extends CamelTestSupport {
#Test
public void noErrorHandlerTest() {
try {
template.sendBody("direct:noErrorHandler", null);
fail();
} catch (Exception e) {
System.out.println("Caught Exception: " + e.getMessage());
}
}
#Override
protected RoutesBuilder createRouteBuilder() throws Exception {
return new RouteBuilder(){
#Override
public void configure() throws Exception {
from("direct:noErrorHandler")
.errorHandler(noErrorHandler())
.log("Throwing error")
.throwException(Exception.class, "Test Exception");
}
};
}
}