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...

    <bean id="myRedeliveryPolicy" class="org.apache.camel.processor.RedeliveryPolicy">
        <property name="maximumRedeliveries" value="${myprop.max}"/>
    </bean>

     <onException>
         <!-- you can define multiple exceptions just adding more exception elements as show below -->
         <exception>com.mycompany.MyFirstException</exception>
         <exception>com.mycompany.MySecondException</exception>

         <!-- here we reference our redelivy policy defined above -->
         <redeliveryPolicy ref="myRedeliveryPolicy"/>
     </onException>

Using fine grained selection using onWhen

Available as of Camel 1.5.1 or later

You can attach an Expression to the exception clause to have fine grained control when a clause should be selected or not. As it's an Expression you can use any kind of code to perform the test. Here is a sample:

{snippet:id=e1|lang=java|url=activemq/camel/trunk/camel-core/src/test/java/org/apache/camel/processor/exceptionpolicy/DefaultExceptionPolicyStrategyUsingWhenTest.java}

In the sample above we have two onException's defined. The first has an onWhen expression attached to only trigger if the message has a header with the key user that is not null. If so this clause is selected and is handling the thrown exception. The 2nd clause is a for coarse gained selection to select the same exception being thrown but when the expression is evaluated to false. Notice: this is not required, if the 2nd clause is omitted, then the default error handler will kick in.

See also

The Error Handler for the general error handling documentation
The Dead Letter Channel for further details.
The Transactional Client for transactional behavior