Groovy is trying to cast a domain object to CGLib version which results in ClassCastException

New update. Hibernate can be taken out of the equation. We have a sample where we get the same error and we are not using any Hibernate, just plain Java.

The exception also occurs in the following code

for(int scanNum = 1; scanNum<6 ; scanNum++) {
            Photo photo = new Photo();
            photo.setScanNum(scanNum);
            trayService.addPhoto(tray, photo);
        }

public Tray addPhoto(Tray tray, Photo photo) {
        TrayPhoto trayPhoto = new TrayPhoto(tray, photo);

public TrayPhoto(Tray tray, Photo photo){
        trayId = tray.getId()
        eventId = tray.getEventId()
        scanNum = photo.getScanNum()
        nextId = -1
        isFirst = false
    }

The line

scanNum = photo.getScanNum()

in the TrayPhoto constructor is where the ClassCastException is occuring.

Here is the decompiled code of the TrayPhoto constructor

public TrayPhoto(Tray tray, Photo photo)
    {
        CallSite acallsite[];
        acallsite = $getCallSiteArray();
        metaClass = $getStaticMetaClass();
        metaClass;
        (MetaClass)ScriptBytecodeAdapter.castToType(metaClass, $get$$class$groovy$lang$MetaClass());
        this;
        JVM INSTR swap ;
        metaClass;
        JVM INSTR pop ;
        Object obj;
        Object obj1;
        Object obj2;
        obj = acallsite[0].call(tray);
        obj;
        trayId = DefaultTypeTransformation.intUnbox(obj);
        obj1 = acallsite[1].call(tray);
        obj1;
        eventId = DefaultTypeTransformation.intUnbox(obj1);
        obj2 = acallsite[2].call(photo);
        obj2;
        scanNum = DefaultTypeTransformation.intUnbox(obj2);
        $const$0;
        nextId = DefaultTypeTransformation.intUnbox($const$0);
        Boolean.FALSE;
        isFirst = DefaultTypeTransformation.booleanUnbox(Boolean.FALSE);
        return;
    }

Sorry that the code didn't keep its indentation, I will upload a text file with all that code.

Please provide a reproducable test case.

The code with indentation.

I would love to be able to do a test case that would cause the issue 100%, but the problem is that it fails part of the time. the code I pasted is the best I can do to provide an example. It really does occur very simply. One thing to note is that there are lots of Annotations in the class for Hibernate, and I have seen many issues with Groovy and Annoations not working, so with this issue, it can be very deeply rooted, or a combination of things involved.

I have download all the Groovy 1.6.5 sources so I can step through that code and see if I notice anything.

As of right now, I think we have to convert the Event and Photo groovy objects into java objects.

To be honest out of the box Groovy is quite broken with Hibernate because Hibernate's proxy generation is not aware of Groovy which causes proxying to happen for methods it shouldn't and weird class cast issues like you're seeing.

To get it working properly in Grails we had to override the way Hibernate creates proxies. See http://github.com/grails/grails/blob/master/grails/src/java/org/codehaus/groovy/grails/orm/hibernate/proxy/GroovyAwareJavassistLazyInitializer.java

Thanks Graeme.

You guys can choose if you want to just close this Jira, if there are already a Jira covering the Hibernate issues, or if it is something that Hibernate would have to change their code.

I just converted the Domain object back to .java and things are much better.

Mark, that doesn't address your comment where Hibernate was taken out of the equation.

@Transactional
public void test() {
  for(int scanNum = 1; scanNum<6 ; scanNum++) {
      Photo photo = new Photo();
      photo.setScanNum(scanNum);
      trayService.addPhoto(tray, photo);
  }
}

public Tray addPhoto(Tray tray, Photo photo) {
    TrayPhoto trayPhoto = new TrayPhoto(tray, photo);
    ...
}

public TrayPhoto(Tray tray, Photo photo){
    trayId = tray.getId()
    eventId = tray.getEventId()
    scanNum = photo.getScanNum()
    nextId = -1
    isFirst = false
} 

The exception occurs on photo.getScanNum(), but as you can see Photo has not yet been persisted.
So why would there be any proxy at that point when Photo was constructed using new?

Excluding Hibernate, does groovy do any type of proxying on its own?

The above test case was a Spring integration test annotated with

@ContextConfiguration(locations="classpath:test.xml")
@RunWith(SpringJUnit4ClassRunner.class)

and Photo and TrayPhoto are annotated @Entity classes.
Is there any way possible for hibernate to automatically proxy a new instance that has yet to be persisted??

Looks like there was some discussion on this in the Hibernate Jira, but no resolution.

http://opensource.atlassian.com/projects/hibernate/browse/HHH-3870

Here's hoping it gets resolved soon.

We converted the Photo object back to Java, but now getting the same issue on another object Studio.

We are trying to use <gorm:session-factory> to see if that would use your workaround?
Do you think that is wise and will fix the issue, or are we just spinning wheels trying?

Thanks

Using grails <gorm /> to instantiate the session factory would solve this problem, but it appears to not be fully implemented as stated in the javadoc.

http://jira.codehaus.org/browse/GRAILS-5290

As this issue has not been updated for 2,5 years I'm closing it. Please reopen if it still occurs with newer versions of Groovy. Thanks!