Hello,

We are using EHCACHE as the second level caching mechanism in our Hibernate project. As part of EHCACHE configuration I want to cache certain associations.

Thus in a hbm file I have added

<cache usage="read-only" />

at the class level and also at the association level.




However due to the addition of

<cache usage="read-only" />

at the association it gives me this error :

Can't write to a readonly object
java.lang.UnsupportedOperationException: Can't write to a readonly object

What is the reason for this ? I can make it work if I make it <cache usage="read-write" />. However I want to keep it read-only.

In the hbm file at the class level, I have stated mutable="false". How do I do that for the association ? Adding mutable as an attribute of 'set' does not seem to work (although it should have).Anyways, although I strongly feel that it is due to mutable issue, it maybe due to somthing else. Any ideas / suggestions ?

Thanks and regards,
Milan

Looks like you are trying to modify the object (or the set)?

Good Point. I should have mentioned it in my original post that I am NOT updating the object(the association).

Thanks,
Milan

Looks like Hibernate thinks the object was updated anyway? May be worth disabling the cache (or setting it to read-write) and looking at the logging output...

Is the exception thrown when you close the session? Assuming you are not also updating objects in the same session, you could prevent Hibernate from flushing: session.setFlushMode(FlushMode.NEVER).