In the setup put the line:
Serial.begin(9600); // serial debugging port
Unless your serial is already being used by
arduino = new Arduino(this, Arduino.list()[1],57600);
//write to arduino
arduino.analogWrite(11, int(redAmount));
arduino.analogWrite(10, int(greenAmount));
arduino.analogWrite(9, int(blueAmount));
Serial.print(int(redAmount));
Serial.println(" redAmount");
Serial.print(int(greenAmount));
Serial.println(" greenAmount");
Serial.print(int(blueAmount));
Serial.println(" blueAmount");
}