colored image to greyscale image conversion

import java.io.File;
import java.io.IOException;
import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;

public class Grayscale
{
    public static void main(String args[])throws IOException
    {
        BufferedImage img = null;
        File f = null;

        // read image
        try
        {
            f = new File("D:\\Inp.jpg");
            img = ImageIO.read(f);
        }
        catch(IOException e)
        {
            System.out.println(e);
        }

        // get image's width and height
        int width = img.getWidth();
        int height = img.getHeight();

        // convert to greyscale
        for (int y = 0; y < height; y++)
        {
            for (int x = 0; x < width; x++)
            {
                // Here (x,y)denotes the coordinate of image
                // for modifying the pixel value.
                int p = img.getRGB(x,y);

                int a = (p>>24)&0xff;
                int r = (p>>16)&0xff;
                int g = (p>>8)&0xff;
                int b = p&0xff;

                // calculate average
                int avg = (r+g+b)/3;

                // replace RGB value with avg
                p = (a<<24) | (avg<<16) | (avg<<8) | avg;

                img.setRGB(x, y, p);
            }
        }

        // write image
        try
        {
            f = new File("D:\\Out.jpg");
            ImageIO.write(img, "jpg", f);
        }
        catch(IOException e)
        {
            System.out.println(e);
        }
    }
}

Java code for watermarking an image

import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

public class WaterMark
{
    public static void main(String[] args)
    {
        BufferedImage img = null;
        File f = null;

        // Read image
        try
        {
            f = new File("input.png");
            img = ImageIO.read(f);
        }
        catch(IOException e)
        {
            System.out.println(e);
        }

        // create BufferedImage object of same width and
        // height as of input image
        BufferedImage temp = new BufferedImage(img.getWidth(),
                    img.getHeight(), BufferedImage.TYPE_INT_RGB);

        // Create graphics object and add original
        // image to it
        Graphics graphics = temp.getGraphics();
        graphics.drawImage(img, 0, 0, null);

        // Set font for the watermark text
        graphics.setFont(new Font("Arial", Font.PLAIN, 80));
        graphics.setColor(new Color(255, 0, 0, 40));

        // Setting watermark text
        String watermark = "WaterMark generated";

        // Add the watermark text at (width/5, height/3)
        // location
        graphics.drawString(watermark, img.getWidth()/5,
                                   img.getHeight()/3);

        // releases any system resources that it is using
        graphics.dispose();

        f = new File("output.png");
        try
        {
            ImageIO.write(temp, "png", f);
        }
        catch (IOException e)
        {
            System.out.println(e);
        }
    }
}

Java program to demonstrate read and write of image

import java.io.File;
import java.io.IOException;
import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;

public class MyImage
{
    public static void main(String args[])throws IOException
    {
        int width = 963;    //width of the image
        int height = 640;   //height of the image

        // For storing image in RAM
        BufferedImage image = null;

        // READ IMAGE
        try
        {
            File input_file = new File("D:\\pic.jpg"); //image file path

            /* create an object of BufferedImage type and pass
               as parameter the width,  height and image int
               type.TYPE_INT_ARGB means that we are representing
               the Alpha, Red, Green and Blue component of the
               image pixel using 8 bit integer value. */
            image = new BufferedImage(width, height,
                                    BufferedImage.TYPE_INT_ARGB);

             // Reading input file
            image = ImageIO.read(input_file);

            System.out.println("Reading complete.");
        }
        catch(IOException e)
        {
            System.out.println("Error: "+e);
        }

        // WRITE IMAGE
        try
        {
            // Output file path
            File output_file = new File("D:\\Out.jpg");

            // Writing to file taking type and path as
            ImageIO.write(image, "jpg", output_file);

            System.out.println("Writing complete.");
        }
        catch(IOException e)
        {
            System.out.println("Error: "+e);
        }
    }//main() ends here
}//class ends here

JavaFX Barchart Example

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.chart.BarChart;
import javafx.scene.chart.CategoryAxis;
import javafx.scene.chart.NumberAxis;
import javafx.scene.chart.XYChart;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;


public class BarChartEx extends Application {

    public void start(Stage stage) {

        initUI(stage);
    }

    private void initUI(Stage stage) {
       
        HBox root = new HBox(); 

        Scene scene = new Scene(root, 480, 330);
        CategoryAxis xAxis = new CategoryAxis();

        NumberAxis yAxis = new NumberAxis();
        yAxis.setLabel("Gold medals");

        BarChart barChart = new BarChart(xAxis, yAxis);
        barChart.setTitle("Olympic gold medals in London");

        XYChart.Series data = new XYChart.Series();

        data.getData().add(new XYChart.Data("USA", 46));
        data.getData().add(new XYChart.Data("China", 38));
        data.getData().add(new XYChart.Data("UK", 29));
        data.getData().add(new XYChart.Data("Russia", 22));
        data.getData().add(new XYChart.Data("South Korea", 13));
        data.getData().add(new XYChart.Data("Germany", 11));

        barChart.getData().add(data);
        barChart.setLegendVisible(false);

        root.getChildren().add(barChart);

        stage.setTitle("BarChart");
        stage.setScene(scene);
        stage.show();

    }

    public static void main(String[] args) {
        launch(args);
    }
}