Demonstrate to Draw Bar Charts in Java

import java.awt.*;
import java.awt.font.*;
import java.awt.geom.*;
import javax.swing.*;
public class BarChart extends JApplet
{
public void init()
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
String v = getParameter("values");
if (v == null) return;
int n = Integer.parseInt(v);
double[] values = new double[n];
String[] names = new String[n];
for (int i = 0; i < n; i++) { values[i] = Double.parseDouble(getParameter("value." + (i + 1))); names[i] = getParameter("name." + (i + 1)); } add(new Component(values, names, getParameter("title"))); } }); } } class Component extends JComponent { public Component(double[] v, String[] n, String t) { values = v; names = n; title = t; } public void paintComponent(Graphics g) { Graphics2D g2 = (Graphics2D) g; if (values == null) return; double minValue = 0; double maxValue = 0; for (double v : values) { if (minValue > v) minValue = v;
if (maxValue < v) maxValue = v;
}
if (maxValue == minValue) return;
int panelWidth = getWidth();
int panelHeight = getHeight();
Font titleFont = new Font("SansSerif", Font.BOLD, 20);
Font labelFont = new Font("SansSerif", Font.PLAIN, 10);
FontRenderContext context = g2.getFontRenderContext();
Rectangle2D titleBounds = titleFont.getStringBounds(title, context);
double titleWidth = titleBounds.getWidth();
double top = titleBounds.getHeight();
double y = -titleBounds.getY();
double x = (panelWidth - titleWidth) / 2;
g2.setFont(titleFont);
g2.drawString(title, (float) x, (float) y);
LineMetrics labelMetrics = labelFont.getLineMetrics("", context);
double bottom = labelMetrics.getHeight();
y = panelHeight - labelMetrics.getDescent();
g2.setFont(labelFont);
double scale = (panelHeight - top - bottom) / (maxValue - minValue);
int barWidth = panelWidth / values.length;
for (int i = 0; i < values.length; i++) { double x1 = i * barWidth + 1; double y1 = top; double height = values[i] * scale; if (values[i] >= 0) y1 += (maxValue - values[i]) * scale;
else
{
y1 += maxValue * scale;
height = -height;
}
Rectangle2D rect = new Rectangle2D.Double(x1, y1, barWidth - 2, height);
g2.setPaint(Color.BLUE);
g2.fill(rect);
g2.setPaint(Color.BLACK);
g2.draw(rect);
Rectangle2D labelBounds = labelFont.getStringBounds(names[i], context);
double labelWidth = labelBounds.getWidth();
x = x1 + (barWidth - labelWidth) / 2;
g2.drawString(names[i], (float) x, (float) y);
}
}
private double[] values;
private String[] names;
private String title;
}

Output: