At JSF
<h:commandButton immediate="true"
If you do, validation will be avoided when you press this button and submit.
That's not a mistake, but I was addicted to using it easily. When immediate = "true", the action method seems to be executed before the backing bean is updated.
Therefore, even if the bean value is acquired by the action method, the old value can be acquired, so the part that is performing the processing that expected the current input value failed.
immediate = "true" wants to skip input check and backing bean update and execute action method immediately! I wonder if it will be used at that time. Like the back button.