how come only one ball changes color?

 I have put in an int2color () object, but it doesnt work in draw(). What am i missing please?

 

Ball ball1;
Ball ball2;

void setup(){
  size (500,500);
  ball1 = new Ball(32);
  ball2 = new Ball (16);
}

void draw(){
  background(0);
  ball1.display();
  ball1.move();
  ball2.display();
  ball2.move();
  if (ball1.intersect(ball2)){
      ball2.int2color();
      ball1.intcolor();
  }
}
 
class Ball{
  float rad;
  float x,y;
  float xspeed,yspeed;
 
  Ball(float _rad){
    rad= _rad;
     x = random(width);
     y = random(height);
     xspeed = random (-5, 2);
     yspeed = random (-5,2);
  }
  void display(){
    ellipse (x,y,rad,rad);
    fill (255);
    if (x>width||x<0){
      xspeed *= -1;}
      if (y>height||y<0){
        yspeed *= -1;}    
  }
   void intcolor(){
    fill (255,0,0);
  }
  void int2color(){
    fill (0,255,0);
  }
 
  void move(){
    x += xspeed;
    y += yspeed;
  }
boolean intersect (Ball other){
  float distance = dist (x, y, other.x, other.y);
  if (distance < rad + other.rad){
    return true;
  }else{
    return false;
  }
}
}