error opening serial port busy proseccing/arduino-servo

Question

Hello i have this processing sketch for my thesis project to move a servo left or right with Emotiv Epoc(Actually I want to send keystrokes r or l).
The first goal is to identify automatically the port. I get an opening serial port busy error .

error opening serial port 'comx'. (port busy)

I think the serial port is open inside the loop so when i try to open it (ser_port = new Serial(this,detected_port,9600); line 73-74) it gets me the error.

Is there a way that i can close it an re open it? (Actually i want a sketch that checks which port has an Arduino, then connect to that port) any help will be greatly appreciated

import processing.serial.*; Serial ser_port;                // for
serial port PFont fnt;                      // for font int
num_ports; boolean device_detected = false; String[] port_list;
String detected_port = "";   void setup() {
    size(400, 200);                         // size of application window
    background(0);                          // black background
    fnt = createFont("Arial", 16, true);    // font displayed in window

    println(Serial.list());

    // get the number of detected serial ports
    num_ports = Serial.list().length;
    // save the current list of serial ports
    port_list = new String[num_ports];
    for (int i = 0; i < num_ports; i++)  {
        port_list[i] = Serial.list()[i];
    } }   void draw() {
    background(0);
    // display instructions to user
    textFont(fnt, 14);
    text("1. Arduino or serial device must be unplugged.", 20, 30);
    text("   (unplug device and restart this application if not)", 20, 50);
    text("2. Plug the Arduino or serial device into a USB port.", 20, 80);

    // see if Arduino or serial device was plugged in
    if ((Serial.list().length > num_ports) && !device_detected) {
        device_detected = true;
        // determine which port the device was plugge into
        boolean str_match = false;
        if (num_ports == 0) {
            detected_port = Serial.list()[0];
        }
        else {
            // go through the current port list
            for (int i = 0; i < Serial.list().length; i++) {
                // go through the saved port list
                for (int j = 0; j < num_ports; j++) {
                    if (Serial.list()[i].equals(port_list[j])) {
                        break;
                    }
                    if (j == (num_ports - 1)) {
                        str_match = true;
                        detected_port = Serial.list()[i];

                    }
                }
            }
        }
    }
    // calculate and display serial port name
    if (device_detected) {
        text("Device detected:", 20, 110);
        textFont(fnt, 18);
        text(detected_port, 20, 150); 
        textFont(fnt, 14);
        text("3.  Now think Right or Left in this Window",20,190);

    } }   

      char valToWrite = 'r' & 'l'; //a value to send as a single byte   

     void keyPressed(){

     // This is the line I'm getting the error!
     ser_port = new Serial(this,detected_port,9600);



    ser_port.bufferUntil(10);
    valToWrite = key;
    ser_port.write(valToWrite); }   

      void keyReleased(){

    valToWrite = 'r' & 'l';   
   ser_port.write(valToWrite); }