Socket Exception - Connection Reset
May 13, 2014
I got the below exception .how to resolve this .It's receiving the data up to 10 min then suddenly below error happening. I have embedded the source code below
java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(Unknown Source)
at java.net.SocketInputStream.read(Unknown Source)
at sun.nio.cs.StreamDecoder.readBytes(Unknown Source)
at sun.nio.cs.StreamDecoder.implRead(Unknown Source)
[Code] .....
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May 28, 2013
I have some embedded systems (with web server) putting their states, sensor values into an XML file.
<sensor1>
<temp>21.4</temp>
<unit>°C</unit>
</sensor1>
Now I played a little with EJB3. I want to start a timer bean in a 10second interval which retrieves the IP of registered devices from a databases, opens client sockets with a Thread Pool and retrieves the XML file over HTTP GET of each device listed in the db.
Is it possbile with EJB3? how to start thread based background services like that within EJB3 timer bean?
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Feb 10, 2014
I have been working with socket programming. I was trying to develop a two way communication from server to client. The data is being received when sent from server to client but there is a problem when I am sending from client to server.
I am getting an error as "Socket is closed" pointing to the line where I have created a BufferedReader. I have simplified some part of my code to be very specific.
Code attached.
import java.io.*;
import java.net.*;
import java.util.*;
public class Server
{
public static void main(String args[])
{
String id="policeone";
int hashcodeid=0;
[Code] ....
Error::
Receiving string from client: 'java.net.SocketException: Socket is closed
at java.net.Socket.getInputStream(Socket.java:872)
at Server.main(Server.java:51)
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Jun 24, 2014
We have a servlet application running under jboss 7.1.1/java 1.7 that sends http requests to another server. Everything works fine for most of the time, but occasionally (from one to a couple of times a day) we get a “Socket closed” exception. I’ve been trying to find out what might be causing this but so far I’ve been unsuccessful. By the way, this has been happening while the application was running under older versions of Jboss/Java so the version might not be that relevant.
Here’s an excerpt from the method where this happens:
. . . . .
try
{
HttpURLConnection conn = (HttpURLConnection) urlEndpoint.openConnection();
conn.setRequestMethod("POST");
conn.setDoInput(true);
conn.setDoOutput(true);
[Code] ....
And here’s what the exception looks like:
. . . . . .
java.net.SocketException: socket closed
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.read(SocketInputStream.java:150)
at java.net.SocketInputStream.read(SocketInputStream.java:121)
at java.io.BufferedInputStream.fill(BufferedInputStream.java:235)
[Code] ....
In my investigation I came across some posts that were mentioning the sockets pool the http connection is keeping, but I’m not sure whether and how this solve the problem I have.
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Jul 27, 2014
Below is a code of a simple file downloader in java. I want to detect an exception when the connection is broken in the middle of downloading a file. Now, I run the code and in the middle of downloading the file, i turn off my wifi with keyboard wifi off button. Doing this the program hangs forever without throwing any exceptions and without terminating. It seems it blocks forever.why is exception not thrown? Secondly, in the following code you can see this line //con.setReadTimeout(2000); which is currently commented out. Removing the comment and running the program, now if connection breaks in the middle by turning off wifi then it waits for 2 seconds and then if it cannot read then it terminates without throwing exception. So, again in this case why is it just terminating and not throwing any exception?
Java Code:
import java.io.FileOutputStream;
import java.net.URL;
import java.net.URLConnection;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;
import java.util.*;
[code]...
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Oct 2, 2014
I tried this program, its guessing game. Where program decide 1 number and user will guess number. I am getting 1 problem. When user want to play game again.the random number remain same. So where i can put reset random in code..? And 1 more question if I want to write driver code for this. What should i transfer to driver code.
import java.util.Random;
import java.util.Scanner;
public class GuessGame {
public static void main(String args[])
{
String choice="y";
[Code] ......
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Dec 2, 2014
I have the following unit test that gives me a null pointer exception. The debugger goes to the finally block right after the line that creates a connection factory. Here's the test:
@Test
public void receiveMessage() throws Exception {
MessageConsumer consumer = null;
ConnectionFactory connectionFactory = null;
Connection connection = null;
Session session = null;
Destination destination = null;
[code]....
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Sep 1, 2014
I have created a JSP page, on click of a particular button, the control moves to the servlet "TestServlet".
This is the code under TestServlet:
import java.io.IOException;
import java.io.PrintWriter;
import java.security.Principal;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;
[Code]...
Now, I have got a comment saying I should get the database connection from connection pool. And one more issue is that I have used the function System.getProperty("user.name") to get the username which i have logged in. But this code will be run on Unix which will not support this function. Any function where I can get the windows username. There is a function getUserPrincipal(), but this function returns a NULL. How to resolve this.
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Jan 11, 2015
I configured a connection pool in tomcat 7. For every database activity I get a connection from the pool. Do I have to close the connection like other regular connection after the database operation is done? If I close the connection will it have any effect on the connection pool?
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Jan 23, 2015
I have to write a program that will generate 20 random circles with random radius lengths. If any of these circles intersect with another, the circle must be blue, and if it does not intersect, the color is red. I must also place a button on the JFrame. If this button is pressed, it needs to clear out the JFrame, and generate a new set of 20 circles following the same color rules. I am extremely new to Java Swing and am really stuck. I have everything working except the button. I cannot get a new set of circles to generate.
import java.awt.Graphics;
import javax.swing.JPanel;
import java.util.Random;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
[Code] ....
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Oct 13, 2009
I have 5 radio buttons in my gui, I have a reset button which I have resetting everything else but now I am looking to remove the dot from the selected RB when you press the reset.
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Aug 14, 2014
I want to use my implemented toolkit while loading applets. So, I have set the Runtime Parameters
-Dawt.toolkit=org.sug.MyToolkit in Java Control panel.
But when it is not picking MyToolkit, instead its default toolkit sun.awt.windows.WToolkit.
I am able to set it perfectly in Java 6 but it is not working in java 7.
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Mar 14, 2014
The problem i believe is that I have the max value set to the first value given out, but every time the loop repeats the Max value gets reset to the next value in the file.
Essentially the program is supposed to read a list of credit card transactions and tell the user which transaction is the highest.
Here's the list of the sample file, note that the number of transactions could change that's why i haven't tried simply passing the values to method.
Bicycle 562.90
Groceries 138.43
Hotel 612.00
import java.io.File;
import java.io.IOException;
import java.util.Scanner;
public class CreditCards {
public static void main(String[] args) throws IOException {
String fileName = "C:/Users/David/Desktop/CreditCard.txt";
File inputFile = new File(fileName);
[Code] ....
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May 2, 2013
I have a HelloWorld.java_:
package com.javapapers.sample.ajax;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
[Code] .....
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Jun 3, 2014
When we have a jsf form to store clients in a ddbb for example and the backing bean is in session scope.... Lets think of a user that requests 3 times the xhtml view with the form to store 3 clients.
1) If we dont reset the backing bean each time the form is processed, he would see the values he sent beforea and it doesnt have much sense, right?
2) Here there is an example of clearing form after submitting : [URL] ...... Clearing the form after submititng is a common practice for the reason of the statement 1, right?
3 ) What is the best or normal approach to reset values in a form? when the user requests it or done automatically by the application after processing a form?
4) Are there known issues about resetting or not resetting the values in a form bean?
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Feb 14, 2014
I am a JSP/Servlet newbie currently adding the first servlets to a web site that had been static all along. My local instance worked great but the servlets did not respond on the test instance. Apparently, my hosting service provider requires me to use an invoker servlet mapping.
<servlet-mapping>
<servlet-name>invoker</servlet-name>
<url-pattern>/servlet/*</url-pattern>
</servlet-mapping>
Adding this to local web.xml broke the application but the servlets respond on test instance (when their calls are not preceded by another servlet call). A Servlet fails when it is called immediately after another servlet has been called.
What I saw happening on test is URL for first call is of the form:
xxx.org/<app-name>/servlet/<servlet-name>?Id=1
And URL for the second call became:
xxx.org/<app-name>/servlet/servlet/<servlet-name>?Id=1
The servlets are invoked using "href=servlet/<servlet-name>?Id="
How can I avoid the inclusion of 'servlet' in the URL and reset the URL to the JSP page it navigates to after processing of the servlet?
P.S.: I am also trying to enable the Invoker servlet on local so I can troubleshoot easier. I went through the changes to Tomcat's web.xml and context.xml. However, my local servlets did not respond even after calling them using "href=<servlet-name>?Id=". Is there a way I can check if my invoker is active?
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Nov 9, 2014
I'm back with a question about the Black Jack assignment. I've created a working game that works for one round, as well as a reset button that's able to clear the board of the old hand. However the runGame() loop, which checks whether a player has played his hand seems to freeze the program the second time around
private void initNewGame(){
dealer.addCard();
for(int i = 0; i < numberofplayers; i++){
players[i].addCard(); //draws card, adds score and paints card to the board
players[i].setStatus(false); //makes the buttons usable in the players[] class
[Code] .....
I know it's probably not optimal having an while loop constantly running to check the status, but I can't seem to figure out why it freezes.
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Jan 24, 2014
I was giving a quick skim to some tutorials on the internet where I have found the exception that is handled is also declared in the throws clause of the method wrapping the try-catch block. For a code representation consider the following:
public void methodName() throws IOException {
try {
...
} catch (IOException ex) {
.... TODO handle exception
}
}
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Nov 6, 2014
I don't understand why the object reference variable 'a' cannot be recast from a thisA object reference to a thisB object reference.Is it the case that once a reference variable is linked to a particular object type then it cannot switch object types later on.I am facing the Java Associate Developer exam soon and I am just clearing up some issues in my head around object reference variable assignment,
class thisA {}
class thisB extends thisA { String testString = "test";}
public class CastQuestion2 {
public static void main(String[] args) {
thisA a = new thisA();
thisB b = new thisB();
[code]....
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Feb 13, 2014
I'm developing a web-based chatting system using JSP and socket.
The problem i am facing is that the sender can send message but on the receiver side we have to manually refresh the page. The sender stays into blocking mode until the receiver refresh its page !
after that i've implemented auto-refresh on the receiver side and "Connection Refused" exception is generated.
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Mar 4, 2014
Currently I have socket of the tcp version.
Java Code:
final ServerSocket serverSocketConn = new ServerSocket(9000);
while (true) {
try {
Socket socketConn1 = serverSocketConn.accept();
new Thread(new ConnectionHandler(socketConn1)).start();
[Code] .....
I managed to convert this final DatagramSocket serverSocketConn = new DatagramSocket (9000);
Now I am stuck here
Socket socketConn1 = serverSocketConn.accept();
new Thread(new ConnectionHandler(socketConn1)).start();
Can I use this or I need to create a manual thread pooling for UDP ?
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May 22, 2014
I can have up to 100,000 simultaneous connections to a udp socket, which needs to be handled by separate threads. Each of the connections talk to a c program on an embedded device that sends and responds with an array of unsigned chars. Now Java does not have an unsigned char type. The closest you can use is a short. But DatagramPacket requires a byte argument:
public class Socket {
public Socket(int port) throws IOException {
new SocketThread().start();
} }
public class SocketThread extends Thread {
protected DatagramSocket socket = null;
[Code] .....
So how can I go about reading and writing unsigned chars over a udp socket?
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Apr 4, 2015
if i send messages as in the code below, is there a way to read only one message, if the client doesn't know how long it is (or if he only knows the maximum length)?in the documentation it says, that the method read(byte[]) reads until no data ist available or end of file is decteted. What does the latter mean? Can i extend the array that i sent by a byte that signals the end? Here is my Code:
Server
public class Server implements Runnable{
ServerSocket server;
HashMap<Short,Socket> clients;
public Server(){
clients = new HashMap<>();
[code]....
Both are startet in seperate threads. At the moment the first output of the client is "12 bytes read", and then continously "-1 bytes read"(because the server closes).
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Sep 21, 2014
I want to download objects (css , jpeg, html ,png ) using sockets in java without using httpurlconnection . How can i do this with simple socket library ?
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Feb 13, 2014
I am new to JSP !! and I'm developing a web-based chatting system using JSP and socket.
The problem I am facing is that the sender can send message but on the receiver side we have to manually refresh the page. The sender stays into blocking mode until the receiver refresh its page !
After that I've implemented auto-refresh on the receiver side and "Connection Refused" exception is generated.
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Sep 26, 2014
I am trying to download object thorugh sockets in java . My code is
String servername = "http://ea-cdn.voxmedia.com"; //(String) innObj.get("value");
String filename = "http://ea-cdn.voxmedia.com/production/vox-40-maps/stylesheets/styles-358f0375.css"; //(String) request.get("url");
Socket socket = new Socket("http://10.10.78.62", 3128);
DataOutputStream bw = new DataOutputStream(
[code]...
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