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The current implementations Camel provides out of the box are:

Non-transacted:

• DefaultErrorHandler is the default error handler in Camel. This error handler does not support a dead letter queue, it will propagate exceptions back to the caller, as if there where no error handler at all. It has a limited set of features.
• Dead Letter Channel which supports attempting to redeliver the message exchange a number of times before sending it to a dead letter endpoint
• LoggingErrorHandler for just catching and logging exceptions
• NoErrorHandler for no error handling

Transacted:

• TransactionErrorHandler is the default error handler in Camel for transacted routes. See the Transactional Client EIP pattern.

These error handlers can be applied in the DSL to an entire set of rules or a specific routing rule as we show in the next examples. Error handling rules are inherited on each routing rule within a single RouteBuilder

Short Summary of the

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Provided Error Handlers

DefaultErrorHandler

The DefaultErrorHandler is the default error handler in Camel. Unlike Dead Letter Channel it does not have any dead letter queue, and do not handle exceptions by default.

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The Dead Letter Channel will redeliver at most 6 times using 1 second delay, and if the exchange failed it will be logged at at ERROR level.

You can configure the default dead letter endpoint to use:

{snippet:id=e3|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/builder/ErrorHandlerTest.java}

<bean id="deadLetterErrorHandler" class="org.apache.camel.builder.DeadLetterChannelBuilder">
  <property name="deadLetterUri" value="log:dead"/>
</bean>

<camelContext errorHandlerRef="deadLetterErrorHandler" xmlns="http://camel.apache.org/schema/spring">
  <!-- ... -->
</camelContext>

or also from Camel 2.3.0 onwards:

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

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

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The LoggingErrorHandler

The logging error handler will log (by default at at ERROR level) whenever an uncaught exception is thrown. The logging category, logger and level may all be defined in the builder.

errorHandler(loggingErrorHandler("mylogger.name").level(LoggingLevel.INFO));

or in Spring DSL:

<bean id="loggingErrorHandler" class="org.apache.camel.builder.LoggingErrorHandler">
  <property name="logName" value="mylogger.name"/>
  <property name="level" value="DEBUG"/>
</bean>

<camelContext errorHandlerRef="loggingErrorHandler" xmlns="http://camel.apache.org/schema/spring">
  ...
</camelContext>

or also from Camel 2.3.0 onwards:

<camel:errorHandler id="loggingErrorHandler" type="LoggingErrorHandler" logName="mylogger.name" level="DEBUG"/>

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

This would create an error handler which logs exceptions using the category category mylogger.name and uses the level level INFO for all log messages created.

from("seda:a")
  .errorHandler(loggingErrorHandler("mylogger.name").level(LoggingLevel.DEBUG))
  .to("seda:b");

Loggers may also be defined for specific routes.

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The NoErrorHandler

The no error handler is to be used for disabling error handling.

errorHandler(noErrorHandler());

or in Spring DSL:

<bean id="noErrorHandler" class="org.apache.camel.builder.NoErrorHandlerBuilder"/>

<camelContext errorHandlerRef="noErrorHandler" xmlns="http://camel.apache.org/schema/spring">
  ...
</camelContext>

or also from Camel 2.3.0 onwards:

<camel:errorHandler id="noErrorHandler" type="NoErrorHandler"/>

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

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Features

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Support by

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Various Error Handlers

Here is a breakdown of which features is supported by the Error Handler(s):

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The following example shows how you can register a global error handler (in this case using the logging handler)

{snippet:id=e1|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/builder/ErrorHandlerTest.java}

{snippet:id=e2|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/builder/ErrorHandlerTest.java}

Spring

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Based Configuration

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The error handler is configured with the errorHandlerRef attribute.

Spring

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Based Configuration Sample

In this sample we configure a Dead Letter Channel on the route that should redeliver at most 3 times and use a little delay before retrying.
First, we configure the reference to to myDeadLetterErrorHandler using the errorHandlerRef attribute on the route tag.

{snippet:id=e1|lang=xml|url=camel/trunk/components/camel-spring/src/test/resources/org/apache/camel/spring/config/DeadLetterChannelRedeliveryConfigTest-context.xml}

{snippet:id=e2|lang=xml|url=camel/trunk/components/camel-spring/src/test/resources/org/apache/camel/spring/config/DeadLetterChannelRedeliveryConfigTest-context.xml}

{snippet:id=example|lang=xml|url=camel/trunk/components/camel-spring/src/test/resources/org/apache/camel/spring/handler/ErrorHandlerDefinitionParser.xml}

Using

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the TransactionalErrorHandler

The TransactionalErrorHandler The transactional error handler is based on spring transaction. This requires the usage of the camel-spring component.
See Transactional Client that has many samples for how to use and transactional behavior and configuration with this error handler.

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