Processing and Arduino Send Number

import processing.serial.*;
byte x;
Serial myPort;  // Create object from Serial class
String val;     // Data received from the serial port
void setup(){
  String COM = Serial.list()[0];
  myPort = new Serial(this, COM, 9600);
  size(100,100);textSize(30);fill(255,255,255);
}
void draw(){
  if(mousePressed){
    myPort.write(x);
    x++;
    delay(100);
    background(0);
    text(x,50,50);
  }
}
void keyPressed(){
  if(key==CODED){
    if (keyCode==UP){myPort.write(1);}
    else if(keyCode==DOWN){myPort.write(2);}
    else if(keyCode==LEFT){myPort.write(3);}
    else if(keyCode==RIGHT){myPort.write(4);}
    }
}