Improve duplicate Id with different associated object error message

[moutyque]

Hello,
Working with Jackson I fell upon this exception:

jackson-annotations/src/main/java/com/fasterxml/jackson/annotation/SimpleObjectIdResolver.java

Line 30 in 9ae15a1

throw new IllegalStateException("Already had POJO for id (" + id.key.getClass().getName() + ") [" + id

It gave me a hard time to understand the issue until I look into the code.
IMO the exception message is unclear. The issue is that we Already had POJO for id and the new and old object are different (the second part is no explicit in the exception hence can be tricky to debug.

Propostion:

throw new IllegalStateException("Different POJO share the same id (" + id.key.getClass().getName() + ") [" + id
                        + "]");

[cowtowncoder]

Ok, I can see how existing exception message is not ideal, but not quite sold on proposed change.
Let's see if we can come up with even better alternative.

"ObjectId conflict: Id (class) [ID] already bound to a POJO, attempt to re-bind to a different POJO" ?
(too complex?)

@pjfanning WDYT? The problem being reported is that a given Object Id is already bound to different Java Object.

[pjfanning]

Ok, I can see how existing exception message is not ideal, but not quite sold on proposed change. Let's see if we can come up with even better alternative.

"ObjectId conflict: Id (class) [ID] already bound to a POJO, attempt to re-bind to a different POJO" ? (too complex?)

@pjfanning WDYT? The problem being reported is that a given Object Id is already bound to different Java Object.

@cowtowncoder Your proposed message seems ok to me. I like the change to lead with ObjectId conflict.

[moutyque]

I do agree with your proposal also. Cordialement Quentin Mouty ***@***.*** Le sam. 12 juil. 2025, 10:29, PJ Fanning ***@***.***> a écrit :

…

*pjfanning* left a comment (FasterXML/jackson-annotations#293) <#293 (comment)> Ok, I can see how existing exception message is not ideal, but not quite sold on proposed change. Let's see if we can come up with even better alternative. "ObjectId conflict: Id (class) [ID] already bound to a POJO, attempt to re-bind to a different POJO" ? (too complex?) @pjfanning <https://github.com/pjfanning> WDYT? The problem being reported is that a given Object Id is already bound to different Java Object. @cowtowncoder <https://github.com/cowtowncoder> Your proposed message seems ok to me. I like the change to lead with ObjectId conflict. — Reply to this email directly, view it on GitHub <#293 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AGCJDALPABKKCFNH5RBZ4K33IDBOBAVCNFSM6AAAAACBGKFAQ6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTANRUHE2DENBZG4> . You are receiving this because you authored the thread.Message ID: ***@***.***>