Challenge 3: A Static Factory Method, origin() — Possible Solution
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Point.java:

public class Point {
    private double x;
    private double y;

    public Point(double x, double y) {
        this.x = x;
        this.y = y;
    }

    public static Point origin() {
        return new Point(0.0, 0.0);
    }

    public String toString() {
        return "(" + x + ", " + y + ")";
    }

    public static void main(String[] args) {
        Point p = Point.origin();
        System.out.println(p);
    }
}

Output:

    (0.0, 0.0)

Explanation:
origin() is called as Point.origin() -- directly on the class, with
no Point instance existing yet at the call site. It must be static
for exactly that reason: an instance method can only be invoked on an
existing object (obj.method()), but here there is no object yet --
producing that very first object is origin()'s whole job. Only after
origin() returns does a real Point instance exist for p to hold.

WHY THIS WORKS AS AN ANSWER
------------------------------
This directly demonstrates the chapter's own claim that static
methods belong to the class rather than an instance, using the same
factory-method shape the chapter introduced (Account's own empty()),
and explains the ordering dependency -- no object exists until the
static method itself creates one.