JEP 427 and objects meant to replace null

[P Holder]

I was just looking at the null handling parts of
JEP 427: Pattern Matching for switch (Third Preview)
and wondering how it would impact the way I code.

I personally go to great efforts to avoid null.  If I need an "out of
band" signal for an object, I make a public static final  special
value to use in the place of null, especially in initializers.

I was wondering if there is any logical way to handle these special
cases? (sorry for the pun)

so if I have

class Shape
{
  public static final Shape UNDEFINED_SHAPE = new Shape();
...
}

could I have

static void testTriangle(Shape s) {
    switch (s) {
        case null, UNDEFINED_SHAPE ->
            System.out.println("An undefined shape");
       case Triangle t
        when t.calculateArea() > 100 ->
            System.out.println("Large triangle");
        default ->
            System.out.println("A shape, possibly a small triangle");
    }
}