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|900px|Java exception hierarchy]]

 
* Java <code>Exception</code> is a standard error. Such item might come from your application or a dependency.
** ''Spring-integration can survive and handle Exceptions''. Moreover, exceptions will be send to the error-channel automatically. They are part of the flow.


* 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 cannot  survive Errors''

 

=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'd like to since 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>