Hi everyone,

first of all I would like to apologize for not be used to forums rules and netiquette, but I'll try to do my best in order to avoid any mess. Here's the question. I wrote a program for reading data sent from my arduino 2009 board to the pc via serial port. The program itself is working fine, but here's the point: I need to manage the error rising from accidental removal of the usb cable which arduino is attached to. Even a generic exception doesn't work and the program crashes. The code part vulnerable to the error should be this

1. void setup()
2. { 
3.   //..... usual setup stuff!
4.   portArbitration() ; //try to interrogate any available port from Serial.list() until it gets the arduino one
5. }
6. 
   
7. void draw() 
8. {
9.   background(0);
10.   while (myPort.available () > 0) 
11.   {
12.      //read value until carriage return
13.     concentration=myPort.readStringUntil(13);
14.     if (concentration != null) 
15.     {
16.       //display values from the sensor in a ControlP5 textfield
17.       sensorDisplay.setValue(concentration);
18. 
    
19.      //write_to_file code (that I have not completed yet ) goes here
20.     }
21.   }
22. }

And when I disconnect usb cable, here's what I get:

1. java.io.IOException: No error in nativeavailable
2. at gnu.io.RXTXPort.nativeavailable(Native Method)
3. at gnu.io.RXTXPort$SerialInputStream.available(RXTXPort.java:1532)
4. at processing.serial.Serial.serialEvent(Unknown Source)
5. at gnu.io.RXTXPort.sendEvent(RXTXPort.java:732)
6. at gnu.io.RXTXPort.eventLoop(Native Method)
7. at gnu.io.RXTXPort$MonitorThread.run(RXTXPort.java:1575)
8. java.lang.NullPointerException
9. at processing.mode.java.runner.Runner.findException(Runner.java:925)
10. at processing.mode.java.runner.Runner.reportException(Runner.java:870)
11. at processing.mode.java.runner.Runner.exceptionEvent(Runner.java:813)
12. at processing.mode.java.runner.Runner$2.run(Runner.java:699)

Is there any try - catch structure I could use to manage this? Maybe is a stupid question, but i'm quite new to Java and OOP. Thank you for every support!