JSF xmlns URI not registered in IntelliJ IDEA

Question

Here is the start of my JSF file:

Answer 1

you could also add "urn:import:<url>"

example: xmlns:d="urn:import:com.mypackage.mylovelycode"

Answer 2

I had the same issue... but in my case, the problem was that by mistake I saved file with extension ".xml". Changing it into ".xhtml" solved the problem