Where do these methods... live?

Processing Beginners
1

Hi, I have a question that may be really stupid but I just can’t quite wrap my head around what’s happening here.

When using methods like void draw() or void mousePressed()… are these part of an interface somewhere? I guess what I’m really asking… is why are we re-specifying the return type if the method already exists?

Thanks for any clarification here…

2

The base class for all sketches that use processing.core is PApplet

simplistic setup() and draw() are provided there and my understanding is that your sketch auto-magically subclasses this (IDE work) and you provide your own variation of those.

3

Adding on to @jay_m’s comment, Processing’s preprocessor takes code (in the Processing IDE) that looks like this…

void setup() {...}

void draw() {...}

…and produces a resulting Java class that looks something like this:

import processing.core.PApplet;

final class JavaVersion extends PApplet {

	public static void main(String[] args) {
		PApplet.main(JavaVersion.class);
	}

    @Override
    void setup() {...}
    
    @Override
    void draw() {...}

}