Suppose you have developed ADF task flow with pages (not page fragments) and later on you decide that these pages should be page fragments, and you convert that taskflow to support page fragments. After conversion, if you get this error
java.lang.IllegalStateException: Attempt to validate an already invalid RegionSite:
Check whether you have used PageController for page or not. If you used then convert it to RegionController. ADF does not give you indication of this. If you want to debug error, do the following:
- Goto bindings of page on which you dropped taskflow containing page fragments.
- In Executables, click the taskflow and set its property "activation" to "immediate"
- Now run and you will get detailed error.
It can also occur if your taskflow is calling any method before page loading and that method is throwing some error.