JFreeChart bar chart

In this example, we will create a bar chart using JFreeChart library.

JFreeChart is a popular Java library for creating charts. JFreeChart allows to create a wide variety of both interactive and non-interactive charts. We can create line charts, bar charts, area charts, scatter charts, pie charts, Gantt charts, and various specialized charts such as wind charts or bubble charts.

JFreeChart Maven dependency

For our projects, we use the below Maven dependency:

<dependency>
    <groupId>org.jfree</groupId>
    <artifactId>jfreechart</artifactId>
    <version>1.5.0</version>
</dependency>

JFreeChart bar chart

A bar chart presents grouped data with rectangular bars with lengths proportional to the values that they represent. The bars can be plotted vertically or horizontally.

The below code example uses a bar chart to show the number of Olympic gold medals per country in London 2012.

package com.java.library.jfreechart;

import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.data.category.CategoryDataset;
import org.jfree.data.category.DefaultCategoryDataset;

import javax.swing.BorderFactory;
import javax.swing.JFrame;
import java.awt.Color;
import java.awt.EventQueue;

public class BarChartExample extends JFrame {

    public BarChartExample() {

        initUI();
    }

    private void initUI() {

        CategoryDataset dataset = createDataset();

        JFreeChart chart = createChart(dataset);
        ChartPanel chartPanel = new ChartPanel(chart);
        chartPanel.setBorder(BorderFactory.createEmptyBorder(15, 15, 15, 15));
        chartPanel.setBackground(Color.white);
        add(chartPanel);

        pack();
        setTitle("Bar chart");
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    private CategoryDataset createDataset() {

    	DefaultCategoryDataset dataset = new DefaultCategoryDataset();
        dataset.setValue(46, "Gold medals", "USA");
        dataset.setValue(38, "Gold medals", "China");
        dataset.setValue(29, "Gold medals", "UK");
        dataset.setValue(22, "Gold medals", "Russia");
        dataset.setValue(13, "Gold medals", "South Korea");
        dataset.setValue(11, "Gold medals", "Germany");

        return dataset;
    }

    private JFreeChart createChart(CategoryDataset dataset) {

        JFreeChart barChart = ChartFactory.createBarChart(
                "Olympic gold medals in London",
                "",
                "Gold medals",
                dataset,
                PlotOrientation.VERTICAL,
                false, true, false);

        return barChart;
    }

    public static void main(String[] args) {

        EventQueue.invokeLater(() -> {

        	BarChartExample ex = new BarChartExample();
            ex.setVisible(true);
        });
    }
}

Run above program will produce the below output: