JFreeChart doesn't appear when I click on button

Question

I see no output for this code in panel, but in console points (X,Y) come out. I searched more and more and nothing.

This is UI class:

/*
 * To chang         


        

Answer 1

this.revalidate(); //is your solution.

It updates the frame after you click the button. Thus, making the chart appear as the frame is updated.

Answer 2

Instead of replacing the chart in your action handler, simply update the relevant series in the chart's dataset. To make the example below self-contained, I've substituted readFile() and changed the return type to List<Double>.

I don't understand what error I make?

Your attempt to add() a new ChartPanel "invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component." The approach shown below obviates the need.

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.util.List;
import java.util.Random;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import javax.swing.AbstractAction;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;

/**
 * @see http://stackoverflow.com/a/37020264/230513
 */
public class Test {

    private final XYSeries signal = new XYSeries("signal");
    private final XYSeriesCollection dataset = new XYSeriesCollection(signal);

    private void display() {
        JFrame f = new JFrame("Test");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JFreeChart chart = ChartFactory.createXYLineChart(
            "Signal chart", "Time(T)", "Voltage(V)", dataset);
        f.add(new ChartPanel(chart));
        JPanel p = new JPanel(new FlowLayout(FlowLayout.RIGHT));
        p.add(new JButton(new AbstractAction("Load signal") {
            @Override
            public void actionPerformed(ActionEvent e) {
                signal.clear();
                List<Double> list = ReadFile.readFile();
                int i = 0;
                for (Double d : list) {
                    signal.add(i++, d);
                }
            }
        }));
        f.add(p, BorderLayout.SOUTH);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    private static class ReadFile {

        private static final Random R = new Random();

        public static List<Double> readFile() {
            List<Double> list = Stream.iterate(4.0, x -> x - (R.nextDouble() / 42))
                .limit(42).collect(Collectors.toList());
            return list;
        }
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Test()::display);
    }
}