Output

onPlayerMove()
        from =  Vector(-44.973586, 63.000000, 184.599402)
        to =    Vector(-44.976534, 63.000000, 184.491422)
        Delta =         Vector(-0.002948, 0.000000, -0.107980)
        Delta (Normalized) =    Vector(-0.027288, 0.000000, -0.999628)
        inFront =       Vector(-45.003822, 63.000000, 183.491795)
        inFront (Block) =       Vector(-46.000000, 63.000000, 183.000000)
onPlayerMove()
        from =  Vector(-44.976534, 63.000000, 184.491422)
        to =    Vector(-44.926589, 63.000000, 184.349126)
        Delta =         Vector(0.049944, 0.000000, -0.142296)
        Delta (Normalized) =    Vector(0.331182, 0.000000, -0.943567)
        inFront =       Vector(-44.595408, 63.000000, 183.405559)
        inFront (Block) =       Vector(-45.000000, 63.000000, 183.000000)
onPlayerMove()
        from =  Vector(-44.926589, 63.000000, 184.349126)
        to =    Vector(-44.899320, 63.000000, 184.271433)
        Delta =         Vector(0.027270, 0.000000, -0.077694)
        Delta (Normalized) =    Vector(0.331182, 0.000000, -0.943567)
        inFront =       Vector(-44.568138, 63.000000, 183.327866)
        inFront (Block) =       Vector(-45.000000, 63.000000, 183.000000)
onPlayerMove()
        from =  Vector(-44.899320, 63.000000, 184.271433)
        to =    Vector(-44.876301, 63.000000, 184.205850)
        Delta =         Vector(0.023019, 0.000000, -0.065582)
        Delta (Normalized) =    Vector(0.331182, 0.000000, -0.943567)
        inFront =       Vector(-44.545120, 63.000000, 183.262283)
        inFront (Block) =       Vector(-45.000000, 63.000000, 183.000000)

Plugin.java

	public void onEnable() {
		TaskInjector.newInstance(this);

		getServer().getPluginManager().registerEvents(new Listener() {
			@EventHandler
			public void onPlayerMove(PlayerMoveEvent event) {
				// TODO Check for same world.

				World world = event.getTo().getWorld();
				Vector from = event.getFrom().toVector();
				Vector to = event.getTo().toVector();

				// Skip when the player is just rotating head.
				if (from.distanceSquared(to) == 0) // distSquared is faster as it doesn't involve a sqrt().
					return;

				System.out.println("onPlayerMove()");
				System.out.println(String.format("\tfrom = \t%s", blockVectorToString(from)));
				System.out.println(String.format("\tto = \t%s", blockVectorToString(to)));

				Vector delta = to.clone().subtract(from);
				System.out.println(String.format("\tDelta = \t%s", blockVectorToString(delta)));
				delta = delta.normalize();
				System.out.println(String.format("\tDelta (Normalized) = \t%s", blockVectorToString(delta)));
				Vector inFrontVector = to.clone().add(delta);
				System.out.println(String.format("\tinFront = \t%s", blockVectorToString(inFrontVector)));

				Location inFrontVectorLoc = inFrontVector.toLocation(world);
				System.out.println(String.format("\tinFront (Block) = \t%s", blockVectorToString(inFrontVectorLoc.getBlock().getLocation().toVector())));

			}

		}, this);

		System.out.println(String.format("[%s] Enabled - Version: %s", getDescription().getName(), getDescription().getVersion()));
	}

	public static String blockVectorToString(Vector v) {
		return String.format("Vector(%8f, %8f, %8f)", v.getX(), v.getY(), v.getZ());
	}