I set my FileUpload component with this params:
<p:fileUpload label="Select image"
mode="advanced"
update="messages"
fileUploadListener="#{fileUploadController.handleFileUpload}"
sizeLimit="1000000"
fileLimit="1"
fileLimitMessage="Only 1 image"
allowTypes="/(\.|\/)(gif|jpe?g|png)$/"/>
<p:growl id="messages" showDetail="true"/>
But if i select more image i don't get any error or warning.
I reproduced the same behavior, but I dont think it's intentional. You can do a little workaround if you use auto="true" because the file will be uploaded immediately. On the other hand you can make sure that your backing bean is just processing the last file uploaded (maybe the user selected a wrong file in the first place and wants to use another one?).
fileLimit="1" only limits the file limit when using mode="advanced" and multiple="true" (see [1]), but that is currently not supported by primefaces (see [2]).
[1] http://forum.primefaces.org/viewtopic.php?f=3&t=14194
[2] https://www.primefaces.org/docs/guide/primefaces_user_guide_6_1.pdf at page 218