Yes, as the FU component sends a request per file and FacesMessage lives only for one request - them will be lost after next one and you will not be able to show them onuploadcomplete. Try to store them on some bean session or conversation scoped as a workaround and show after upload complete. The validation mechanism improvements for FU already planned in jira.
Thanks for the prompt reply!
I understand the problem.
What about using validator attribute? I tried (by registering validator using Seam annotations) and it doesn't even get called. I also found a JIRA which says this.
Also some more links that say the same:
Is there a way to call a validator?
currently validator will not helps you as messages will be lost in any way. So try to workaround it by storing messages manually.
Alright. Thanks! Storing manually works fine.