This case is when i put outbound references inside multicast in camel DSL then i'm unable to handle error thrown by outbound components. Let's say i trying to save file to non existing directory, after that i get FileNotFoundException and finally i can't catch this exception by the code below:

errorHandler(deadLetterChannel("switchyard://ErrorOutbound"));    

onException(Throwable.class).to("switchyard://ErrorOutbound");

from("switchyard://InboundService")

    .multicast()

        .to("switchyard://Outbound")

        .to("switchyard://Outbound")

    .end()

.end();

Noting is going to switchyard://ErrorOutbound. So error handler or onException are unable to handle this, but when i wrap component into directs or pipelines then it start working as i expect.

errorHandler(deadLetterChannel("switchyard://ErrorOutbound"));    

onException(Throwable.class).to("switchyard://ErrorOutbound");

from("switchyard://InboundService")

    .multicast()

        .pipeline().to("switchyard://Outbound").end()

        .pipeline().to("switchyard://Outbound").end()

    .end()

.end();

Second case:

errorHandler(deadLetterChannel("switchyard://ErrorOutbound"));    

onException(Throwable.class).to("switchyard://ErrorOutbound");

from("switchyard://InboundService")

    .multicast()

        .to("direct:Outbound")

        .to("direct:Outbound")

    .end()

.end();

from("direct:Outbound")

     .to("switchyard://Outbound")

So my question is: This is the usual case how multicast should be used in switchyard? I didn't found any mention about this in documentation. The version i tested was: EAP 6.1, switchayrd 1.1 and EAP 6.4, switchyard 2.0. Similar code developed in pure camel does not needs this trick to make it work.

errorHandler(deadLetterChannel("file:C:/tmp/zzz?fileName=error-${date:now:yyyyMMddHHmmssSSS}"));

onException(Throwable.class).to("file:C:/tmp/zzz?fileName=error-${date:now:yyyyMMddHHmmssSSS}");

from("file:C:/tmp/xxx/pending")

     .multicast()

          .to("file:C:/tmp/yyy?autoCreate=false")

          .to("file:C:/tmp/yyy?autoCreate=false")

     .end()

.end();