Apache Camel: errorHandler vs onException?

Question

What's the difference between:

<camel:errorHandler id="deadLetterErrorHandler" type="DeadLetterChannel" 
        deadLetterUri="log:dead">

<camel:camelContext errorHandlerRef="deadLetterErrorHandler">
    ...
</camel:camelContext>

And:

<onException>
    ...
</onException>

According to this article , using them both in conjunction is a "powerful combination". How so? What roles do they each individual assume, and how do they complement each other?

Answer 1

The errorHandler is used to handle any uncaught Exception that gets thrown during the routing and processing of a message. Conversely, onException is used to handle specific Exception types when they are thrown. Check out this article to see how to use onException .

Answer 2

If the action you need to perform for each type of exception is different, use onException. It lets you define error handling on a per exception basis.

onException(xxxException.class).to("activemq:xxxFailed"); onException(yyyException.class).to("activemq:yyyFailed");

If you just need a generic handler, go with errorHandler. For all type of errors, the same processing will be performed.