View source for Spring-integration error handling



=Spring-integration error management=

Java uses Errors and Exceptions to signal application non-expected events and runtime errors. Here is the hierarchy: 

[[File:Exception-hierarchy.png|700px|Java exception hierarchy]]

 
* Java <code>Exception</code> is a standard error. Such item might come from your application or a dependency.
* Java <code>Error</code> should be reserved to <code>java.lang</code> and JVM. Errors should only occur in case of emergency and fatal issue. However some libraries do throw Error instead of Exception. :(

Spring-integration behaviour:
* Spring-integration can survive and handle Exceptions. Exceptions will be send to the error-channel automatically = they are part of the flow.
* Spring integration cannot survive Errors. if such an even occurs the framework will stop working and block your application!


 

=How to avoid Spring-integration failure?=

As some library are throwing <code>Error</code> we must handle <code>Throwable</code> events!


In the code you must do the following every-time your processing a Spring-integration message:

<syntaxhighlight lang=java>
@Service
public class MyBean implements IMyBean {
   private static final Logger LOGGER = Logger.getLogger(MyBean.class);
 
   [...]
 
   @Transactional(propagation = Propagation.REQUIRES_NEW)
   @Override
   public Bean springImportMessageProcess(Bean params) {
       try {
       } catch(Exception e) { 
            LOGGER.error("Something wrong happened, failed to process message!", e);
            // You can throw the exception if you like. Spring-integration will redirect it to its error channel.
            throw e;
       } catch(Throwable e) {
           // You must NOT push the error to the caller !! It will break Spring-integration
           LOGGER.fatal("Something wrong happened, failed to process message! The JVM or a key library has encountered a FATAL error!", e);
       }
   }
}
</syntaxhighlight>