for (int i = 0; i <= 24; i++) {

    final Minute min = new Minute(0, i, 28, 04, 2019);
    final Minute min1 = new Minute(30, i, 28, 04, 2019);
    final Marker currentEnd = new ValueMarker((double) min.getFirstMillisecond());
    final Marker currentEnd1 = new ValueMarker((double) min1.getFirstMillisecond());

    currentEnd1.setLabel("HH" + ((i * 2) - 1 + 3));
    currentEnd.setLabel("HH" + ((i * 2) - 2 + 3));

    currentEnd.setLabelAnchor(RectangleAnchor.TOP);
    currentEnd.setLabelFont(font3);
    currentEnd.setLabelTextAnchor(TextAnchor.TOP_LEFT);
    currentEnd1.setLabelAnchor(RectangleAnchor.TOP);
    currentEnd1.setLabelFont(font3);
    currentEnd1.setLabelTextAnchor(TextAnchor.TOP_LEFT);
    currentEnd.setPaint(Color.red);
    currentEnd1.setPaint(Color.red);
    plot1.addDomainMarker(currentEnd1);
    plot1.addDomainMarker(currentEnd);

}