import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.SystemColor;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JProgressBar;
import javax.swing.SwingUtilities;
import javax.swing.border.EmptyBorder;
import javax.swing.plaf.basic.BasicProgressBarUI;

public class FarbigeStatusAnzeige {

    private final static int MAX = 4000, MIN = 0;

    public FarbigeStatusAnzeige() {
        init();
    }

    private void init() {
        FarbigeProgressBar bar = new FarbigeProgressBar(MIN, MAX);
        bar.setValue(MAX);
        bar.setStringPainted(true);

        final Runnable runnable = new Runnable() {
            int rot = 0, gruen = 255;
            double faktor = MAX / 255 / 2;

            public void run() {
                for (int i = MAX; i >= MIN; i--) {
                    if (i < MAX / 5 * 2) {
                        rot += faktor / 5;
                    }
                    if (i < MAX / 10) {
                        gruen -= faktor / 25;
                        rot += faktor / 15;
                    }

                    rot = rot > 255 ? 255 : rot;
                    rot = rot < 0 ? 0 : rot;
                    gruen = gruen > 255 ? 255 : gruen;
                    gruen = gruen < 0 ? 0 : gruen;
                    bar.setForeground(new Color(rot, gruen, 0));
                    try {
                        Thread.sleep(3);
                    } catch (InterruptedException ex) {
                    }
                    bar.setValue(i);
                }
                // Farbigkeit auf Ausgangswert zuruecksetzen
                rot = 0;
                gruen = 255;
                bar.updateUI();
            }
        };

        JButton button = new JButton("start");
        button.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                Thread thread = new Thread(runnable);
                thread.start();
            }
        });
        JFrame frame = new JFrame("Farbige Statusanzeige");
        frame.setLayout(new BorderLayout());
        frame.add(button, BorderLayout.SOUTH);
        frame.add(bar, BorderLayout.CENTER);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> new FarbigeStatusAnzeige());
    }
}

class FarbigeProgressBar extends JProgressBar {

    public FarbigeProgressBar(int start, int end) {
        setMinimum(start);
        setMaximum(end);
        setForeground(SystemColor.window);
        setBackground(SystemColor.window);
        setBorder(new EmptyBorder(3, 5, 3, 5));
        Dimension size = new Dimension(300, 20);
        setPreferredSize(size);
        setMaximumSize(size);
        setMinimumSize(size);
        BasicProgressBarUI ui = new BasicProgressBarUI() {
            protected Color getSelectionForeground() {
                return Color.BLACK;
            }

            protected Color getSelectionBackground() {
                return Color.BLACK;
            }
        };
        setUI(ui);
    }
    @Override
    public void updateUI() {
        setUI(getUI());
    }
}