Nice way to have your private variables editable in a external window.

BackgroundColor

import control.ControlFrame;
import processing.core.PApplet;

public class BackgroundColor {

    private final PApplet p;
    
    @ControlElement(properties = {"min=0", "max=255"}, x = 10, y = 10)
    private float red = 0;
    
    @ControlElement(properties = {"min=0", "max=255"}, x = 10, y = 10)
    private float green = 0;
    
    @ControlElement(properties = {"min=0", "max=255"}, x = 10, y = 10)
    private float blue = 0;
    
    public BackgroundColor(PApplet p) {
        this.p = p;
        new ControlFrame(this, 200, 200);
    }
    
    public void update() {
        p.background(red, green, blue);
    }
   

ControlFrame

package control;

import controlP5.ControlP5;
import processing.core.PApplet;
import java.awt.*;

public class ControlFrame extends PApplet {

    int w;
    int h;

    public void setup() {
        size(w, h);
        frameRate(25);
    }

    public void draw() {
        background(0);
    }

    public ControlFrame(Object parent, int theWidth, int theHeight) {

        String name = parent.getClass().getSimpleName();
        w = theWidth;
        h = theHeight;

        createFrame(name);
        createControlP5(parent, name);
    }

    private void createFrame(String name) {
        Frame f = new Frame(name);
        f.add(this);

        this.init();

        f.setTitle(name);
        f.setSize(w, h);
        f.setLocation(100, 100);
        f.setResizable(false);
        f.setVisible(true);
    }

    private void createControlP5(Object parent, String name) {
        ControlP5 cp5 = new ControlP5(this);
        cp5.addControllersFor(name, parent);
    }
}

This is awesome! Thanks for sharing.