I know it is because of PApplet name (from what I heard processing sketch is just a PApplet running in java)
when I copied the code on a blank sketch it worked.
You don’t need to reply but keep that in mind if you have any issues : D
when I copied the code on a blank sketch it worked.
Was true in former versions, not anymore.
Besides, when you have a class of a name A make sure you don’t save your Sketch with the same name A.