COBCH1644 Cannot use KEY phrase with WRITE statement applied to lists

You cannot use the KEY phrase in these circumstances, but you can use the KEY phrase with the REWRITE statement, which enables you to write to a specific location in your list.

class-id ListsClass.      
method-id listsDemo.
procedure division.
declare stringList as list[string]
create stringList

perform varying i as binary-long from 1 by 1 until i > 5
               write stringList from "item " & i
end-perform

write stringlist from "New item" key 2    *> this is incorrect
rewrite stringlist from "New item" key 2  *> but this will update list at key 2

end method.

end class.