title: Apache Camel: errorHandler vs onException?
body: <p>What's the difference between:</p>
  
  <pre><code>&lt;camel:errorHandler id="deadLetterErrorHandler" type="DeadLetterChannel" 
          deadLetterUri="log:dead"&gt;
  
  &lt;camel:camelContext errorHandlerRef="deadLetterErrorHandler"&gt;
      ...
  &lt;/camel:camelContext&gt;
  </code></pre>
  
  <p>And:</p>
  
  <pre><code>&lt;onException&gt;
      ...
  &lt;/onException&gt;
  </code></pre>
  
  <p>According to <a href="http://camel.apache.org/error-handler.html" rel="noreferrer">this article</a>, 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?</p>