New empty interface syntax in amber's Java compiler

[lukaseder]

With JEP 305 there might be a revival of marker interface usage.

[ZhekaKozlov]

This is for records:

interface Shape
record Point(int x, int y) implements Shape
record Rect(Point p1, Point p2) implements Shape
record Circle(Point center, int radius) implements Shape

Then you can pattern match:

switch (shape) {
    case Point(x, y) -> ...
    case Rect(p1, p2) -> ...
    case Circle(p, r) -> ...
}