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Using Hessian Data Format

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<dependency>
 <groupId>org.apache.camel</groupId>
 <artifactId>camel-hessian</artifactId>
 <version>x.y.z</version>
</dependency>

...

replacing x.y.z with your version of Camel core.
Java DSL
Marshalling
 
from("direct:in")
 .marshal().hessian();
Unmarshalling
...
from("direct:back")
 .unmarshal().hessian();
Spring DSL
Marshalling
...
<camelContext id="camel" xmlns="http://camel.apache.org/schema/spring">
 <route>
 <from uri="direct:in"/>
 <marshal ref="hessian"/>
 </route>
</camelContext>
Unmarshalling
 
<camelContext id="camel" xmlns="http://camel.apache.org/schema/spring">
 <route>
   <from uri="direct:back"/>
   <unmarshal ref="hessian"/>
 </route>
</camelContext>
...
Hessian Data Format internally relies on Hessian library provided by Caucho 
<dependency>
  <groupId>com.caucho</groupId>
  <artifactId>hessian</artifactId>
  <version>4.0.38</version>
</dependency>
...