Java: relojes, fechas, tiempos, midiento con precisión

Dejo aquí un codekata en Java de copia y pega para medir tiempos.

import java.time.Clock;
import java.util.Date;

class Main {
    public static void main(String[] args) throws Exception {
        System.out.println();
        System.out.println("Clock.systemUTC().millis() = " + Clock.systemUTC().millis());
        System.out.println("System.currentTimeMillis() = " + System.currentTimeMillis());
        System.out.println("         System.nanoTime() = " + System.nanoTime());
        System.out.println("              (new Date()) = " + (new Date()));
        System.out.println("   (new Date()).getTime()) = " + (new Date()).getTime());
        System.out.println();

        Thread.sleep(3000);

        System.out.println();
        System.out.println("Clock.systemUTC().millis() = " + Clock.systemUTC().millis());
        System.out.println("System.currentTimeMillis() = " + System.currentTimeMillis());
        System.out.println("         System.nanoTime() = " + System.nanoTime());
        System.out.println("              (new Date()) = " + (new Date()));
        System.out.println("   (new Date()).getTime()) = " + (new Date()).getTime());
        System.out.println();

        /*
         * Se recomienda usar nanoTime(), aunque es cíclico, 
         * porque es más rápido de obtener que
         * currentTimeMillis().
         */
        Long startTime = System.nanoTime();
        Thread.sleep(1000);
        Long endTime = System.nanoTime();
        System.out.println("Nanosegundos consumidos = " + (endTime - startTime));
    }
}

Si todo va bien, se tiene que ver por pantalla algo tal que así: