프로세싱 오픈소스를 찾아서 사용하려는데

import processing.serial.*;

Serial myPort;
int rad = 0;
float cx, cy;
ArrayList<Ball> balls = new ArrayList<Ball>();

void setup()
{
  size(400, 400);
  cx = width/2;
  cy = height*2/3;
  noFill();
 
  println(Serial.list());
  myPort = new Serial(this, Serial.list()[0], 9600);
}

void draw(){
  background(0);
  stroke(0, 255, 36);
  arc(cx, cy, width, height, PI, TWO_PI, CHORD);
  float r = TWO_PI-map(rad, 0, 360, 0, TWO_PI);
  line(cx, cy, cx + cos(r)* width/2, cy + sin(r)* height/2);
  updateBalls();
  displayBalls();
}

void updateBalls(){
  for(int i = balls.size()-1 ; i > -1 ; i--){
  balls.get(i).update();
  if(balls.get(i).isDead())
    balls.remove(i); 
  }
}

void displayBalls(){
  for(int i = 0 ; i < balls.size() - 1 ; i++){
  balls.get(i).display(); 
  }
}

void serialEvent(Serial p){
  String inString = p.readStringUntil('\n');
  if(inString != null){
  if(inString.startsWith("r")){
    String[] strings = inString.trim().replace("r","").split("d");
    if(strings.length > 1){
      rad = Integer.parseInt(strings[0]);
      int distance = Integer.parseInt(strings[1]);
      if(distance != 0){
           balls.add(new Ball(cx, cy, rad, distance)); 
      }
    }
  }
  } 
}

이렇게 입력하면  

exit status 1
'import' does not name a type

이런식으로 오류가 납니다 무엇이 문제인지 알수있을까요?