Everytime I try to run the program I keep getting the "NullPointerException" error message. Along with this other stuff:
Exception in thread "Animation Thread" java.lang.NullPointerException
     at Project_2_.setup(Project_2_.java:40)
     at processing.core.PApplet.handleDraw(PApplet.java:1402)
     at processing.core.PApplet.run(PApplet.java:1327)
     at java.lang.Thread.run(Thread.java:613)

Here's my code.

Code:

String[] rows = {
  "grass",
  "water",
  "water",
  "water",
  "water",
  "grass",
  "road",
  "road",
  "road",
  "road",
  "grass"};

Lane[] allLanes;		     

int grassColor = color(18, 173, 5);
int waterColor = color(18, 23, 227);
int roadColor = color(17, 17, 18);

void setup () {
  size (700,500);
  smooth ();
  allLanes = new Lane[rows.length];
  for(int i = 0; i < allLanes.length; i++) allLanes[i].drawLane();
}

void draw () {
  for(int i = 0; i < allLanes.length; i++) allLanes[i].drawLane();

}

class Lane {
  color laneColor = color(0);
  int rowHeight = 0;
  int yPos = 0;
  
  Lane(String type, int yRow){
    if(type.equals("grass")) this.laneColor = grassColor;
    if(type.equals("water")) this.laneColor = waterColor;
    if(type.equals("road")) this.laneColor = roadColor;
    
    this.rowHeight = height / rows.length;
    this.yPos = this.rowHeight * yRow;
  }
  
  int drawLane() {
    fill (this.laneColor);
    
    rect (0,this.yPos, width, this.rowHeight);
    
    return yPos;
  }
}


 

Any help would be appreciated.