Using Processing-0111

strokeWeight() doesn't work on JAVA2D on normal mode, but it does work on
present mode.



void setup(){
size(200,200);
background(255);
stroke(0);
noFill();

strokeWeight(5);
}


void draw(){

}

void mouseDragged(){
line(pmouseX,pmouseY,mouseX,mouseY);
}

i'm guessing you have something wrong with your graphics card or its
drivers. this works fine for me and i assume most everyone else because
this would be a major bug and we'd be hearing about it a lot more if
strokeWeight() were just plain broken.