I am using

• Windows 7
• Arduino MEGA ADK
• I have ran everything as administrator and I got rid of UAC.
• I have temporarily disabled Anti-virus and re-ran the program
• Com port is COM3
  

Everything I do in Arduino works fine. I can read, write and all the other Serial functions with Arduino.
 
My problem comes with Processing; for some reason I can not write to the port. I can read the port though. 

I am following the example code verbatim; I just took out the comments to make it easier to read.

When I run Serial.list()[0] I get only 1 option: "COM3". I have tried the code with Serial.list()[0] and "COM3".

If I change brightness = Serial.read(); --> brightness = Serial.parseInt(); I can just type in a number between 0 and 255 and it changes the brightness accordingly.

Can someone help figure out why I can not write to the "COM3" Port with Processing?

Arduino Code:

1. const int ledPin = 9;
   
   void setup()
   {
     Serial.begin(9600);
     pinMode(ledPin, OUTPUT);
   }
   
   void loop() {
     byte brightness;
   
     if (Serial.available()) {
       brightness = Serial.read();
       analogWrite(ledPin, brightness);
     }
   }
   

Processing Code:

1. import processing.serial.*;
    Serial port;
    
    void setup() {
    size(256, 150);
    
    println("Available serial ports:");
    println(Serial.list());
    
    port = new Serial(this, Serial.list()[0], 9600); 
    
    }
    
    void draw() {
    for (int i = 0; i < 256; i++) {
    stroke(i);
    line(i, 0, i, 150);
    }
    
    port.write(mouseX);
    }