<p>What is the difference between the value and itemValue attribute of the radiobutton in Jsf?</p>

From this IBM article
Adding row selection to a JSF datatable using radio buttons
:
The
attribute id
is for the component value of the Radio Button Group. It will be bound to the Value field
The attribute selectedRowId is for the
item value
of the radio button, and will be bound to the item value field