Develop Reference

Could not find or load main class SerialTestGET

I am trying to execute the program on Linux , raspberry pi and getting error
Could not find or load main class SerialTestGET.
the program:
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;
import java.net.HttpURLConnection;
import java.net.URL;
public class SerialTestGET implements SerialPortEventListener {
SerialPort serialPort;
static int sensorValue = 0;
/** 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);
sendGet(inputLine);
} catch(Exception e) {
System.err.println(e.toString());
serialPort.removeEventListener();
serialPort.close();
}
}
// Ignore all the other eventTypes, but you should consider the other ones.
}
// HTTP GET request
public void sendGet(String inputLine) throws Exception {
try {
//if difference is more than 3 then send data to SAP HANA
if (inputLine != null && inputLine.length() > 0 && Math.abs(sensorValue - Integer.parseInt(inputLine)) > 3) {
sensorValue = Integer.parseInt(inputLine);
//Considering that A001 sensor is connection with this raspberry pie for now
//we can even pass this with command line but for simplicityhardcoding it
//Replace with your HANA server URL and port number
String url = " ";
url = url + inputLine;
URL obj = new URL(url);
HttpURLConnection con = (HttpURLConnection) obj.openConnection();
// optional default is GET
con.setRequestMethod("GET");
//add request header
//con.setRequestProperty("User-Agent", USER_AGENT);
int responseCode = con.getResponseCode();
if (responseCode == 200) {
System.out.println("OK value:" + inputLine);
} else {
System.out.println("Error: Response code " + responseCode);
}
}
System.out.println("OK value: Less than 3");
} catch(Exception e) {
System.err.println(e.toString());
serialPort.removeEventListener();
serialPort.close();
}
}
public static void main(String[] args)
throws Exception {
SerialTestGET main = new SerialTestGET();
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");
}
}
all files are placed in the required folder
I am running the file from the path java file is located.

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.

Serial Port Data Issue

I have a network configuration as:
Arduino--Xbee--> <--Xbee-Arduino--> Java App on PC
I had burnt a code into the Sender node to send 1s continuously to the Receiver. But what i see is that even after burning a new code into the Sender to send different values, i keep getting the 1s in the receiver end and not the latest values. How do i get over this problem? Is there a way to flush the previous unwanted data?
The code that i use is from a tutorial that i found in the arduino website. Copy pasting the same below:
Receiver Code: Java
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/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() {
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");
}
}

I had burnt a code into the Sender node to send 1s continuously to the Receiver. But what i see is that even after burning a new code into the Sender to send different values, i keep getting the 1s in the receiver end and not the latest values.
How do i get over this problem?
You shall reflash your Arduino. Try reflashing with 2s instead of 1s, and back, you'll see it'll stop sending 1s.
Is there a way to flush the previous unwanted data?
The data itself is gone away on every unplugging of your Arduino.
It looks like your Arduino code did not get uploaded to the board, either you had a connection problem, or your new arduino code is not compiling. Have a good look at the error message the IDE compiler should be returning.

How to call a string to appear in another class in same package

I have this class called Main.java. In this the output is shown by inputLine which is a string taken serially from the com port. I want this string value to be used in some other class which is in the same default package. How do I call this string in other class? I have made a static and declared it outside the method. Now do I call in other class. When I try calling it in other class by Main.inputLine=1 then it says incomparable types.
Also I'm attaching a snapshot of the error: http://oi45.tinypic.com/2gvo5u9.jpg
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.lang.String;
import java.util.Enumeration;
public class Main implements SerialPortEventListener
{
SerialPort serialPort;
/** The port we're normally going to use. */
private static final String PORT_NAMES[] = {
"COM30", // Windows
};
/**
* A BufferedReader which will be fed by a InputStreamReader
* converting the bytes into characters
* making the displayed results code page independent
*/
public BufferedReader input;
/** The output stream to the port */
public 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() {
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 static String inputLine;
public synchronized void serialEvent(SerialPortEvent oEvent) {
if (oEvent.getEventType() == SerialPortEvent.DATA_AVAILABLE) {
try {
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 {
Main main = new Main();
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");
}
}

You're trying to compare two things and one of them is an Object (String). Use equals(Object o).
(Besides, comparison between primitives is done using ==.
You're trying to compare to an integer value. You need to wrap the integer value to a String for this to make much sense.
You want:
if(Main.inputLine.equals("1"))
{
...
}

If you are trying to assign 1 to Main.inputLine then use the following :
Main.inputLine="1"
instead of
Main.inputLine=1
And if you are comparing the String to check for 1 then use the following:
Main.inputLine.equals("1");
instead of
Main.inputLine == "1"