Processing saving empty PDF

[TimoL]

@jb4x

import processing.pdf.*;

void setup() {
  size(500, 500);
  background(255);
  beginRecord(PDF, "frame-####.pdf");
}

void draw () {
}

void mousePressed() {
  circle(mouseX, mouseY, 50);
}

void keyPressed() {
  if (key == 's') {
    endRecord();
    exit();
  }
}

Oh I see! thanks you so much