Develop Reference

JVM Closing with Java result 255 error

I write a Java code to receive data from arduino using RXTX Library through COM ports. When Java receiving and printing it in the console if the arduino suddenly removed then JVM closing with error JAVA Result 255. how to catch that error.When arduino suddenly removed it should print "device removed".
package arduino.recieve;
import gnu.io.CommPortIdentifier;
import gnu.io.SerialPort;
import gnu.io.SerialPortEvent;
import gnu.io.SerialPortEventListener;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.util.Enumeration;
import java.util.TooManyListenersException;
public class NewClass implements SerialPortEventListener {
SerialPort serialPort = null;
private static final String PORT_NAMES[] = {
// "/dev/tty.usbmodem", // Mac OS X
// "/dev/usbdev", // Linux
// "/dev/tty", // Linux
// "/dev/serial", // Linux
"COM3"};
private String appName;
private BufferedReader input;
private OutputStream output;
private static final int TIME_OUT = 1000; // Port open timeout
private static final int DATA_RATE = 9600; // Arduino serial port
public boolean initialize() {
try {
CommPortIdentifier portId = null;
Enumeration portEnum = CommPortIdentifier.getPortIdentifiers();
// Enumerate system ports and try connecting to Arduino over each
//
System.out.println("Trying:");
while (portId == null && portEnum.hasMoreElements()) {
// Iterate through your host computer's serial port IDs
//n2
CommPortIdentifier currPortId = (CommPortIdentifier) portEnum.nextElement();
System.out.println(" port" + currPortId.getName());
for (String portName : PORT_NAMES) {
if (currPortId.getName().equals(portName)
|| currPortId.getName().startsWith(portName)) {
// Try to connect to the Arduino on this port
//
// Open serial port
serialPort = (SerialPort) currPortId.open(appName, TIME_OUT);
portId = currPortId;
System.out.println("Connected on port" + currPortId.getName());
break;
}
}
}
if (portId == null || serialPort == null) {
System.out.println("Oops... Could not connect to Arduino");
return false;
}
// set port parameters
serialPort.setSerialPortParams(DATA_RATE,
SerialPort.DATABITS_8,
SerialPort.STOPBITS_1,
SerialPort.PARITY_NONE);
// add event listeners
try {
serialPort.addEventListener(this);
} catch (TooManyListenersException e) {
{
System.out.println(" Too Many Listeners ");
}
}
serialPort.notifyOnDataAvailable(true);
// Give the Arduino some time
try {
Thread.sleep(2000);
} catch (InterruptedException ie) {
}
return true;
} catch (Exception e) {
e.printStackTrace();
}
return false;
}
//
// Handle serial port event
//
public synchronized void serialEvent(SerialPortEvent oEvent) {
try {
switch (oEvent.getEventType()) {
case SerialPortEvent.DATA_AVAILABLE:
if (input == null) {
input = new BufferedReader(new InputStreamReader(serialPort.getInputStream()));
}
String inputLine = input.readLine();
System.out.println(inputLine);
break;
default:
break;
}
} catch (Exception e) {
System.out.println("Hello");
}
}
public static void main(String[] args) throws Exception {
NewClass test = new NewClass();
test.initialize();
}
}

There are several other event types generated by the serial port that you could maybe try and detect to see if one happens when the arudino gets disconnected. Unfortunately, it doesn't look like there is a DTR event which would probably be the best indicator that something has gone wrong, but the SerialPort class does have an isDTR() method. You could be checking that periodically and if that goes false, then it probably means you've lost the connection to the arduino. You could maybe do that check in a separate thread, or perhaps on every CTS change event.
serialPort.notifyOnDataAvailable(true);
serialPort.notifyOnCTS(true);
...
switch (oEvent.getEventType()) {
case SerialPortEvent.DATA_AVAILABLE:
if (input == null) {
input = new BufferedReader(new InputStreamReader(serialPort.getInputStream()));
}
String inputLine = input.readLine();
System.out.println(inputLine);
break;
case SerialPortEvent.CTS:
if (!serialPort.isDTR()) {
// do something
}
break;
default:
break;
}
Probably having a small worker thread that just checks DTR status would be a better solution though.

10 sec+ delay in processing Arduino Serial input in Java

What I wish to do:
Read Serial.println from my Arduino(COM3) without majoy delay in time
What my situation is:
This Java program delays roughly 20 seconds in Serial input.
This has been achieved by the Arduino IDE Serial monitor. I wanted to embed the serial monitor code into my Java application.
Following attaches useful code (This program is supposed to be ran on a computer receiving Serial.):
package arduino;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStream;
import gnu.io.CommPortIdentifier;
import gnu.io.SerialPort;
import gnu.io.SerialPortEvent;
import gnu.io.SerialPortEventListener;
import java.util.Enumeration;
public class SerialTest implements SerialPortEventListener {
SerialPort serialPort;
/** The port we're normally going to use. */
private static final String PORT_NAMES[] = {"COM3"};
/**
* A BufferedReader which will be fed by a InputStreamReader
* converting the bytes into characters
* making the displayed results codepage independent
*/
private BufferedReader input;
/** The output stream to the port */
private OutputStream output;
/** Milliseconds to block while waiting for port open */
private static final int TIME_OUT = 2000;
/** Default bits per second for COM port. */
private static final int DATA_RATE = 50000;
public void initialize() {
// the next line is for Raspberry Pi and
// gets us into the while loop and was suggested here was suggested http://www.raspberrypi.org/phpBB3/viewtopic.php?f=81&t=32186
//System.setProperty("gnu.io.rxtx.SerialPorts", "/dev/ttyACM0");
CommPortIdentifier portId = null;
Enumeration portEnum = CommPortIdentifier.getPortIdentifiers();
//First, Find an instance of serial port as set in PORT_NAMES.
while (portEnum.hasMoreElements()) {
CommPortIdentifier currPortId = (CommPortIdentifier) portEnum.nextElement();
for (String portName : PORT_NAMES) {
if (currPortId.getName().equals(portName)) {
portId = currPortId;
break;
}
}
}
if (portId == null) {
System.out.println("Could not find COM port.");
return;
}
try {
// open serial port, and use class name for the appName.
serialPort = (SerialPort) portId.open(this.getClass().getName(),
TIME_OUT);
// set port parameters
serialPort.setSerialPortParams(DATA_RATE,
SerialPort.DATABITS_8,
SerialPort.STOPBITS_1,
SerialPort.PARITY_NONE);
// open the streams
input = new BufferedReader(new InputStreamReader(serialPort.getInputStream()));
output = serialPort.getOutputStream();
// add event listeners
serialPort.addEventListener(this);
serialPort.notifyOnDataAvailable(true);
} catch (Exception e) {
System.err.println(e.toString());
}
}
/**
* This should be called when you stop using the port.
* This will prevent port locking on platforms like Linux.
*/
public synchronized void close() {
if (serialPort != null) {
serialPort.removeEventListener();
serialPort.close();
}
}
/**
* Handle an event on the serial port. Read the data and print it.
*/
public synchronized void serialEvent(SerialPortEvent oEvent) {
if (oEvent.getEventType() == SerialPortEvent.DATA_AVAILABLE) {
try {
String inputLine=null;
if (input.ready()) {
inputLine = input.readLine();
System.out.println(inputLine);
}
} catch (Exception e) {
System.err.println(e.toString());
}
}
// Ignore all the other eventTypes, but you should consider the other ones.
}
public static void main(String[] args) throws Exception {
SerialTest main = new SerialTest();
main.initialize();
Thread t=new Thread() {
public void run() {
//the following line will keep this app alive for 1000 seconds,
//waiting for events to occur and responding to them (printing incoming messages to console).
try {Thread.sleep(1000000);} catch (InterruptedException ie) {}
}
};
t.start();
System.out.println("Started");
}
}
Following attaches useful code supposed to ran on Arduino, involves using arcade joystick. I tested it without problems in Serial Monitor, just thought I would attach it in.
/*
The Joystick Adapter to Snake Display
Joystick connected to DIGITAL port 5 - 2
*/
//Define pins
const int joyA = 5;
const int joyB = 4;
const int joyC = 3;
const int joyD = 2;
//Begin.
void setup(){
pinMode(joyA,INPUT);
pinMode(joyB,INPUT);
pinMode(joyC,INPUT);
pinMode(joyD,INPUT);
Serial.begin(9600);
}
void loop(){
boolean a = isaxisPressed(joyA);
boolean b = isaxisPressed(joyB);
boolean c = isaxisPressed(joyC);
boolean d = isaxisPressed(joyD);
if(a){
Serial.println("A");
}else if(b){
Serial.println("B");
}else if(c){
Serial.println("C");
}else if(d){
Serial.println("D");
}else{
Serial.println("Z");
}
}
boolean isaxisPressed(int port){
pinMode(port,OUTPUT);
digitalWrite(port,HIGH);
pinMode(port,INPUT);
return !digitalRead(port);
}

Serial Port not detecting using Java

I am trying to connect to my serial port "COM6", but now I cannot connect to it. I tried printing out the list of serial ports available using portId.getName(). It shows a list of serial ports available but COM6 is not showing there.
This is my Java code:
portList = CommPortIdentifier.getPortIdentifiers();
while (portList.hasMoreElements()) {
portId = (CommPortIdentifier) portList.nextElement();
if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) {
if (portId.getName().equals("COM6")) {
//if (portId.getName().equals("/dev/term/a")) {
try {
serialPort = (SerialPort)
portId.open("Arduino", 2000);
} catch (PortInUseException e) {
System.out.println("Error1 is "+ e);
}
try {
outputStream = serialPort.getOutputStream();
} catch (IOException e) {
System.out.println("Error2 is "+ e);
}
try {
serialPort.setSerialPortParams(9600,
SerialPort.DATABITS_8,
SerialPort.STOPBITS_1,
SerialPort.PARITY_NONE);
} catch (UnsupportedCommOperationException e) {
System.out.println("Error3 is "+ e);
}
try{
byte data1 = 1;
outputStream.write(data1);
System.out.println("helo");
System.out.println(data1);
}catch(IOException e){
System.out.println("Error 3: " + e);
}
}
}
}
serialPort.close();
I have checked the COM6 in my device manager. It shows available. If I run the same com port in vb it works perfectly. Can anyone help me with this problem. Thank you.

I guess you are trying to communicate with an Arduino? If so, you have to install the Arduino IDE - there is also the RXTX library included, which is very similar to the Java Communication API.
Then you can try this code, which is very similar to yours:
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStream;
import gnu.io.CommPortIdentifier;
import gnu.io.SerialPort;
import gnu.io.SerialPortEvent;
import gnu.io.SerialPortEventListener;
import java.util.Enumeration;
public class SerialTest implements SerialPortEventListener {
SerialPort serialPort;
/** The port we're normally going to use. */
private static final String PORT_NAMES[] = {
"/dev/tty.usbserial-A9007UX1", // Mac OS X
"/dev/ttyACM0", // Raspberry Pi
"/dev/ttyUSB0", // Linux
"COM3", // Windows
};
/**
* A BufferedReader which will be fed by a InputStreamReader
* converting the bytes into characters
* making the displayed results codepage independent
*/
private BufferedReader input;
/** The output stream to the port */
private OutputStream output;
/** Milliseconds to block while waiting for port open */
private static final int TIME_OUT = 2000;
/** Default bits per second for COM port. */
private static final int DATA_RATE = 9600;
public void initialize() {
// the next line is for Raspberry Pi and
// gets us into the while loop and was suggested here was suggested http://www.raspberrypi.org/phpBB3/viewtopic.php?f=81&t=32186
System.setProperty("gnu.io.rxtx.SerialPorts", "/dev/ttyACM0");
CommPortIdentifier portId = null;
Enumeration portEnum = CommPortIdentifier.getPortIdentifiers();
//First, Find an instance of serial port as set in PORT_NAMES.
while (portEnum.hasMoreElements()) {
CommPortIdentifier currPortId = (CommPortIdentifier) portEnum.nextElement();
for (String portName : PORT_NAMES) {
if (currPortId.getName().equals(portName)) {
portId = currPortId;
break;
}
}
}
if (portId == null) {
System.out.println("Could not find COM port.");
return;
}
try {
// open serial port, and use class name for the appName.
serialPort = (SerialPort) portId.open(this.getClass().getName(),
TIME_OUT);
// set port parameters
serialPort.setSerialPortParams(DATA_RATE,
SerialPort.DATABITS_8,
SerialPort.STOPBITS_1,
SerialPort.PARITY_NONE);
// open the streams
input = new BufferedReader(new InputStreamReader(serialPort.getInputStream()));
output = serialPort.getOutputStream();
// add event listeners
serialPort.addEventListener(this);
serialPort.notifyOnDataAvailable(true);
} catch (Exception e) {
System.err.println(e.toString());
}
}
/**
* This should be called when you stop using the port.
* This will prevent port locking on platforms like Linux.
*/
public synchronized void close() {
if (serialPort != null) {
serialPort.removeEventListener();
serialPort.close();
}
}
/**
* Handle an event on the serial port. Read the data and print it.
*/
public synchronized void serialEvent(SerialPortEvent oEvent) {
if (oEvent.getEventType() == SerialPortEvent.DATA_AVAILABLE) {
try {
String inputLine=input.readLine();
System.out.println(inputLine);
} catch (Exception e) {
System.err.println(e.toString());
}
}
// Ignore all the other eventTypes, but you should consider the other ones.
}
public static void main(String[] args) throws Exception {
SerialTest main = new SerialTest();
main.initialize();
Thread t=new Thread() {
public void run() {
//the following line will keep this app alive for 1000 seconds,
//waiting for events to occur and responding to them (printing incoming messages to console).
try {Thread.sleep(1000000);} catch (InterruptedException ie) {}
}
};
t.start();
System.out.println("Started");
}
}
The code comes from the Arduino Playground, I'm not able to try it out now, but I connected an Arduino two or three months ago with this code (Windows 8, 64Bit). There are also other methods described in the post, as well as all necessary requirements (e.g. classpath variables) - check them out in your system setting.
Hope it helps.

java not seeing connected device COM4

java is not seeing the arudino on COM4 the code seems to be working
package tester;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStream;
import gnu.io.CommPortIdentifier;
import gnu.io.SerialPort;
import gnu.io.SerialPortEvent;
import gnu.io.SerialPortEventListener;
import java.util.Enumeration;
public class SerialTest implements SerialPortEventListener {
SerialPort serialPort;
/** The port we're normally going to use. */
private static final String PORT_NAMES[] = {
"/dev/tty.usbserial-A9007UX1", // Mac OS X
"/dev/ttyACM0", // Raspberry Pi
"/dev/ttyUSB0", // Linux
"COM4", // Windows
};
/**
* A BufferedReader which will be fed by a InputStreamReader
* converting the bytes into characters
* making the displayed results codepage independent
*/
private BufferedReader input;
/** The output stream to the port */
private OutputStream output;
/** Milliseconds to block while waiting for port open */
private static final int TIME_OUT = 2000;
/** Default bits per second for COM port. */
private static final int DATA_RATE = 9600;
public void initialize() {
// the next line is for Raspberry Pi and
// gets us into the while loop and was suggested here was suggested http://www.raspberrypi.org/phpBB3/viewtopic.php?f=81&t=32186
System.setProperty("gnu.io.rxtx.SerialPorts", "/dev/ttyACM0");
CommPortIdentifier portId = null;
Enumeration portEnum = CommPortIdentifier.getPortIdentifiers();
//First, Find an instance of serial port as set in PORT_NAMES.
while (portEnum.hasMoreElements()) {
CommPortIdentifier currPortId = (CommPortIdentifier) portEnum.nextElement();
for (String portName : PORT_NAMES) {
if (currPortId.getName().equals(portName)) {
portId = currPortId;
break;
}
}
}
if (portId == null) {
System.out.println("Could not find COM port.");
return;
}
try {
// open serial port, and use class name for the appName.
serialPort = (SerialPort) portId.open(this.getClass().getName(),
TIME_OUT);
// set port parameters
serialPort.setSerialPortParams(DATA_RATE,
SerialPort.DATABITS_8,
SerialPort.STOPBITS_1,
SerialPort.PARITY_NONE);
// open the streams
input = new BufferedReader(new InputStreamReader(serialPort.getInputStream()));
output = serialPort.getOutputStream();
// add event listeners
serialPort.addEventListener(this);
serialPort.notifyOnDataAvailable(true);
} catch (Exception e) {
System.err.println(e.toString());
}
}
/**
* This should be called when you stop using the port.
* This will prevent port locking on platforms like Linux.
*/
public synchronized void close() {
if (serialPort != null) {
serialPort.removeEventListener();
serialPort.close();
}
}
/**
* Handle an event on the serial port. Read the data and print it.
*/
public synchronized void serialEvent(SerialPortEvent oEvent) {
if (oEvent.getEventType() == SerialPortEvent.DATA_AVAILABLE) {
try {
String inputLine=input.readLine();
System.out.println(inputLine);
} catch (Exception e) {
System.err.println(e.toString());
}
}
// Ignore all the other eventTypes, but you should consider the other ones.
}
public static void main(String[] args) throws Exception {
SerialTest main = new SerialTest();
main.initialize();
Thread t=new Thread() {
public void run() {
//the following line will keep this app alive for 1000 seconds,
//waiting for events to occur and responding to them (printing incoming messages to console).
try {Thread.sleep(1000000);} catch (InterruptedException ie) {}
}
};
t.start();
System.out.println("Started");
}}
seems to be working but all i get in console is
WARNING: RXTX Version mismatch
Jar version = RXTX-2.2pre1
native lib Version = RXTX-2.2pre2
Could not find COM port.
Started
i looked in to the jar version being off but rxtx asked for it in there stable release

Why are you assuming that it will be always "COM4" on windows ? Maybe try to get the com port like this (from http://www.programcreek.com/java-api-examples/index.php?api=gnu.io.CommPortIdentifier):
public static List<String> getSerialPorts(){
List<String> vp=new ArrayList<String>();
Enumeration portList=CommPortIdentifier.getPortIdentifiers();
while (portList.hasMoreElements()) {
CommPortIdentifier portId=(CommPortIdentifier)portList.nextElement();
if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) {
vp.add(portId.getName());
}
}
return vp;
}

As an alternative to RxTx and the (deprecated) Java Communications API I had luck with jSerialComm
I made a dialog box with a drop down choice of 127 com ports (without the reserved) as the first thing to let the app know which COM port is in use. Then used it in the constructor for the next new class instance.

sending integers from Java to Arduino uno on serial port

I have an issue in my serial communication between Java and arduino board, arduino can send Java bytes and Java is able to print them, Java is taking them as inputs. My problem is when I tend to use the serial port as an output for Java to send java with streams (Buffered, dataoutput...), and no byte is received by Arduino, and this is verified because i asked Arduino to send the bytes received and the it's always zero.can anyone give an advice? appreciate it.
My java code is the following:
package Arduino;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import gnu.io.CommPortIdentifier;
import gnu.io.SerialPort;
import gnu.io.SerialPortEvent;
import gnu.io.SerialPortEventListener;
import gnu.io.UnsupportedCommOperationException;
import java.util.Enumeration;
public class SerialClass implements SerialPortEventListener {
public static int ch = 2;
public SerialPort serialPort;
/** The port we're normally going to use. */
private static final String PORT_NAMES[] = {
"/dev/tty.usbserial-A9007UX1", // Mac OS X
"/dev/ttyUSB0", // Linux
"COM19", // Windows
};
public static BufferedReader input;
public static BufferedWriter output;
//public static BufferedOutputStream out= new BufferedOutputStream(output);
//public static DataOutputStream data= new DataOutputStream(out);
/** Milliseconds to block while waiting for port open */
public static final int TIME_OUT = 2000;
/** Default bits per second for COM port. */
public static final int DATA_RATE = 9600;
public void initialize() {
CommPortIdentifier portId = null;
Enumeration portEnum = CommPortIdentifier.getPortIdentifiers();
//First, Find an instance of serial port as set in PORT_NAMES.
while (portEnum.hasMoreElements()) {
CommPortIdentifier currPortId = (CommPortIdentifier) portEnum.nextElement();
for (String portName : PORT_NAMES) {
if (currPortId.getName().equals(portName)) {
portId = currPortId;
break;
}
}
}
if (portId == null) {
System.out.println("Could not find COM port.");
return;
}
try {
// open serial port, and use class name for the appName.
serialPort = (SerialPort) portId.open(this.getClass().getName(),
TIME_OUT);;
// set port parameters
serialPort.setSerialPortParams(DATA_RATE,
SerialPort.DATABITS_8,
SerialPort.STOPBITS_1,
SerialPort.PARITY_NONE);
// open the streams
input = new BufferedReader(new InputStreamReader(serialPort.getInputStream()));
output= new BufferedWriter(new OutputStreamWriter(serialPort.getOutputStream()));
// add event listeners
serialPort.addEventListener(this);
serialPort.notifyOnDataAvailable(true);
serialPort.notifyOnOutputEmpty(true);
} catch (Exception e) {
System.err.println(e.toString());
}
}
public synchronized void close() {
if (serialPort != null) {
serialPort.removeEventListener();
serialPort.close();
System.out.println("port closed");
}
}
public static synchronized void writeData() {
System.out.println("I'm in...");
try {
output.write(ch);
output.close();
System.out.println("Sent: " + ch);
} catch (Exception e) {
System.out.println("could not write to port");
}
}
public synchronized void serialEvent(SerialPortEvent oEvent) {
if (oEvent.getEventType() == SerialPortEvent.DATA_AVAILABLE) {
try {
String inputLine=input.readLine();
// input.close();
System.out.println(inputLine);
} catch (Exception e) {
System.err.println(e.toString());
}
}
}
public static void main(String[] args) throws Exception {
SerialClass main = new SerialClass();
main.initialize();
SerialClass.writeData();
}
}
My arduino code is:
byte valeur;
int val;
int led = 13;
char buffer[10];
void setup()
{
Serial.begin(9600);
pinMode(led, OUTPUT);
}
void loop(){
delay(10000);
//val= Serial.parseInt();
//Serial.println( val );
if ( Serial.available ()) {
Serial.println("In if");
Serial.readBytes( buffer , 10 );
//val = valeur - '0';
//Serial.println( val ) ;
Serial.println( buffer[0] , DEC ) ;
if( buffer[0] == 2 ) { //Switch on the LED, if the received value is 1.
Serial.println("Val = 2");
digitalWrite(led, HIGH);
}
else if( buffer[0] == 1) { //Switch off the LED, if the received value is 1.
Serial.println("Val = 1");
digitalWrite(led, LOW);
}
}
else{
Serial.readBytes( buffer , 10 );
Serial.println( buffer[0] , DEC ) ;
Serial.println( "No data Available" );
}
// Serial.println("Succesfully received.");
}
and the result in java is (after uploading the arduino code to arduino uno):
I'm in...
Sent: 2
0
No data Available

I managed to send a char to arduino by using jserialcomm library. The method looks like this:
// imports I make in my class
import javax.swing.*;
import java.awt.FlowLayout;
import java.awt.event.*;
import com.fazecast.jSerialComm.*;
import java.io.PrintWriter;
code in method
System.out.println("connect");
port = SerialPort.getCommPort("COM5"); // change if different
port.setComPortTimeouts(SerialPort.TIMEOUT_SCANNER,0,0);
port.openPort();
//port.setBaudRate(9600);
System.out.println(port.getBaudRate());
try {Thread.sleep(600); } catch(Exception e) {} // I think this sleep is a must until it opens
System.out.println(port.isOpen());
if(port.isOpen()) {
System.out.println("port open!");
try {Thread.sleep(500); } catch(Exception e) {}
PrintWriter output = new PrintWriter(port.getOutputStream());
output.write(2);
try {Thread.sleep(800); } catch(Exception e) {}
output.flush();
System.out.println("char sent");
try {Thread.sleep(600); } catch(Exception e) {}
port.closePort();
}
}
else {
// disconnect from the serial port
//port.closePort();
}
}