VectorHelper.java

    public static List<Vector> rotateX(List<Vector> vectors, double degrees) {
        List<Vector> result = new ArrayList<>(vectors.size());
        double cos = Math.cos(Math.toRadians(degrees));
        double sin = Math.sin(Math.toRadians(degrees));
        for (Vector target : vectors) {
            result.add(new Vector(
                    target.getX(),
                    cos * target.getY() - sin * target.getZ(),
                    sin * target.getY() + cos * target.getZ()));
        }
        return result;
    }

    public static List<Vector> rotateY(List<Vector> vectors, double degrees) {
        List<Vector> result = new ArrayList<>(vectors.size());
        double cos = Math.cos(Math.toRadians(degrees));
        double sin = Math.sin(Math.toRadians(degrees));
        for (Vector target : vectors) {
            result.add(new Vector(
                    cos * target.getX() - sin * target.getZ(),
                    target.getY(),
                    sin * target.getX() + cos * target.getZ()));
        }
        return result;
    }

    public static List<Vector> rotateZ(List<Vector> vectors, double degrees) {
        List<Vector> result = new ArrayList<>(vectors.size());
        double cos = Math.cos(Math.toRadians(degrees));
        double sin = Math.sin(Math.toRadians(degrees));
        for (Vector target : vectors) {
            result.add(new Vector(
                    cos * target.getX() - sin * target.getY(),
                    sin * target.getX() + cos * target.getY(),
                    target.getZ()));
        }
        return result;
    }