Java: Missing Features

Java: Missing Features
infoq.com

Structural typing would really go against the grain of the language, and i have a very hard time believing it would actually be useful. What method name is currently widely used with the same semantics across many classes, without being specified by an interface or base class? I can't think of one. There used to be close(), but that's been dealt with. Are there others?

Collection literals seem like a poor idea when there are so many different collection implementations. If i say:

  List list = {1, 2, 3};

  List list = new ArrayList(1, 2, 3);
  List list = ArrayList.of(1, 2, 3);

Maps are a bit harder, because you need a way to describe pairs. In most projects i work on, i end up creating some helper methods that let me write:

  Map map = map(entry("Java", true), entry("Go", false));

Something like algebraic data types would be good, though. You can already implement un-extendable classes using mild hacks:

    public abstract class Shape {
    
        private Shape() {}
    
        public static class Circle {
            public static Circle of(int radius) {
                return new Circle(radius);
            }
    
            public final int radius;
    
            private Circle(int radius) {
                this.radius = radius;
            }
        }
    
        public static class Rectangle {
            public static Rectangle of(int width, int height) {
                return new Rectangle(width, height);
            }
    
            public final int width, height;
    
            private Rectangle(int width, int height) {
                this.width = width;
                this.height = height;
            }
        }
    
    }

There are various madmen out on the edge of town trying to create terse approaches to this by meddling with forces beyond mortal knowledge:

https://github.com/poetix/mtuples

But i can't see that going mainstream.

Honest question: is there ever an acceptable case for having such a long String in memory?