import java.util.Map;
import java.util.HashMap;

// This program demonstrates why concurrent collections are
// better suited for concurrent applications.
// Using HashMap prevents this program from terminating.

class RegularMap {
	static Map<String, Point> points;

	static void read(String key) {
		Point v;
		while ((v = points.get(key)) == null);
		System.out.println(v);
	}

	public static void main(String[] args) throws InterruptedException {
		String key = "hello";
		points = new HashMap<>();
		Thread t = new Thread(() -> read(key));
		t.start();
		Thread.sleep(100);
		points.put(key, new Point(2, 2));
		t.join();
	}
}