pgraphics.java

PGraphics gStuff;
int w = 400;
int h = 300;

void setup () {
  size(w, h); 
  gStuff = createGraphics(w, h);
}

void draw() {
  drawStuff(gStuff);
  image(gStuff, 0, 0);
}

void drawStuff (PGraphics g) {
  g.beginDraw();
  g.ellipse(100, 100, 50, 50);
  g.endDraw();
}