JAXB Unmarshaller not unlocking after failure

[lafual]

Hi,
In Windows I am reading a file that "should" contain XML using @InboundChannelAdapter FileReadingMesageSource and passing on to @Transformer UnmarshallingTransformer.

If the un-marshall works, the correct object is forwarded. When the XML is invalid or not the file didn't contain XML a MessageTransformerException is forwarded.

When the un-marshall is successful, the incoming file is un-locked and I can remove it from the incoming directory. However, when I get a MessageTransformerException the file's lock is not released. When I try to move it get java.nio.file.FileSystemException: The process cannot access the file because it is being used by another process

In the FileReadingMessageSource I have tried without setLocker, setLocker with NIOFileLocker and an implementation of FileLocker which creates an additional file with a .locked extension. None of these solutions work.

I am using the following to Transform;

@Bean
public Jaxb2Marshaller unmarshaller() {
   Jaxb2Marshaller x = new Jaxb2Marshaller();
   x.unmarshaller(MyClass.class);
   return x;
}

@Bean
@Transformer
public UnmarshallingTranformer umt() {
   return new UnmarshallingTransformer(unmarshaller());
}

How do I cause the lock to be released?

Shouldn't the transformer somehow share/re-use the lock of the original file reader? It seems as if it is using its own locking and not releasing after failure.

[artembilan]

Confirmed.

Now need to figure out how to fix...

[artembilan]

OK. I found that xcerces opens an InputStream for the file XMLEntityManager to build an Entity.ScannedEntity.
This entity is closed in case of XMLEntityManager.endEntity() when we have already parsed the current entity and ready to go for the next one, what is not a case for us because of that failure during parsing.

It was probably fixed in some later Java version, but it really still fails for me on Java 8 on Windows...

I will try to workaround it with an explicit InputStream reading in the UnmarshallingTranformer instead of delegation to the target JaxB impl...

[artembilan]

The fix is not reviewed yet.

[artembilan]

Fixed according merged PR with an appropriate back-port to all the supported versions.

[lafual]

Thanks very much for the fast turn-around!

FYI - I was using Java 10 (the 'last chance saloon' before Java 11 and modules), not 8.

I managed to work around the problem by adding a FileToStringTransformer before the UnmarshallingTransformer, so it was dealing with a String and not a File.

[artembilan]

Thanks, @lafual , for feedback! So, sounds like the problem remains in the Java 10 as well, but anyway we can't rely on the latest Java version because of backward compatibility with existing application based on our Spring artifacts.

Nice trick with the FileToStringTransformer though! 👍