ColorPicker.java

import java.awt.Color;
import java.awt.Robot;
import java.awt.AWTException;
import java.awt.MouseInfo;
import java.awt.Point;

public class ColorPicker {

    public static void main(String[] args) {

    System.out.println("Press Ctrl+C to exit");

    while(true) {
        try {
            Robot robot = new Robot();

            Point p = MouseInfo.getPointerInfo().getLocation();
                Color color = robot.getPixelColor(p.x, p.y);

                System.out.print(
                    "Color: " + color.getRed() + " "
                    + color.getGreen() + " "
                    + color.getBlue() 
                    + "       \r");

            } catch (AWTException e) {
                System.out.println("Can't run at headless environment");
                break;
            }
        }
    }
}