#Processing, 37 chars:

void draw(){text("Hello World",0,9);}

Various things used to reduce strokes:

• Sketch window is spawned by default; no need to manually create it
• Using draw is shorter than setup (although the text is then redrawn each frame)
• Uses default size, background, fill, font, and font size
• You don't actually need all 10 pixels height for the text

Processing, 37 chars:

void draw(){text("Hello World",0,9);}

Various things used to reduce strokes:

• Sketch window is spawned by default; no need to manually create it
• Using draw is shorter than setup (although the text is then redrawn each frame)
• Uses default size, background, fill, font, and font size
• You don't actually need all 10 pixels height for the text