Socket Closed Exception Being Thrown
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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Oct 10, 2014
need to navigate/render a jsp when a custom exception is thrown from a code block in my app.for that in web.xml I have configured the error handling
<error-page>
<exception-type>com.exampl.RecordNotFoundException</exception-type>
<location>/WEB-INF/errorpages/recordnotfound.jsp</location>
</error-page>
Code block
@RequestMapping(value = "/record", method = RequestMethod.GET)
public ModelAndView getPages() throws RecordNotFoundException{
throw new RecordNotFoundException("E888", "This is custom message X");
}
My questions are:
Is this the correct way to invoke a jsp when my code throws an exception?Do I need a try catch block to handle the thrown RecordNot Found Exception, if yes how would I navigate to the jsp from the catch block?
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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 4, 2014
I am getting the above error and am not sure which direction to proceed. In the class, the only way we have discussed getting user input is by System.in.read. I have searched and apparently found better methods for getting user input, but wanted to stick with what has been presented thus far.
Assignment Directions:
1. Create a new class named “valuemethod”
2. Create a new method named “Main”
3. In Main Write the code that will call the method EnterPay and YearlySal
4. Create a new method named “EnterPay”
5. In the EnterPay method Write the code that asks the user to input their hourly wage. Use the formula to calculate their yearly salary: wage * 2040. Return the yearly salary to the main method
6. In the main method write the code that will display this: “Your yearly salary is:
Java Code:
package valuemethod;
public class Valuemethod
{
public static void main(String[] args)
//throws java.io.IOException -- moved to EnterPay
[Code] .....
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Apr 21, 2014
I just wanna confirm that when a certain processing throws an exception even when said exception happens inside doFilter, any servlet container will never proceed to the next filter right?
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May 2, 2015
I am attempting to create a very simple game where two squares move around and each can see the other square moving. This is a multi-player game over a TCP network using JavaFX. I am getting an illegal state exception when I call requestFocus(). This is my server:
public class GameServer extends Application {
ObjectOutputStream p1out;
ObjectOutputStream p2out;
int PLAYER1 = 1;
int PLAYER2 = 2;
[Code] .....
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May 27, 2014
Sometimes a nullpointerexception is thrown, in some cases null is easily printed as a value of a variable without an exception being thrown.
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Oct 19, 2014
In my cs class, we have to write a program that throws an exception if the user enters a negative number, the program should prompt the user to enter only positive numbers and then let them retype the number. But everytime I throw an exception, my program gets suspended.
What am I doing wrong, or is there no way to continue a program if an exception is thrown? Does the program automatically get suspended when an exception is thrown?
try{
do
{
N = kb.nextDouble();
if(N<0) {
throw new NegativeArraySizeException();
}
else
j++;
}
while(j==0);
fill.size(N);
}
catch(NegativeArraySizeException e) {
System.out.println("The number you entered must be positive. Please try again.");
}
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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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Aug 15, 2014
I'm want to call another statement within the same resultSet. But it gives an error that the result set is closed.
public static void updateAlarmStatus(int status) {
ResultSet rs = null;
database.restartDatabase();
try {
rs = database
.executeQuery("Select alarmId from alarms where alarmDate = '"
[Code] ....
I googled it and came to know that resultSet is automatically closed if we call another statement within in. I've also tried creating the connection again before the second statement but of no use.
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Mar 19, 2014
I have opened up an input file using
File input=new File("hello.txt")..
Then I have created a scanner object that reads data from the file.
Scanner read_file=new Scanner (input).
my question is when closing the files why can't I just do input.close() since that is also closing the file?
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Apr 28, 2014
I am working with java project which is kind of charting room..but the problem is when am writing the query for listing the message in the conversation the error prevail in my eclipse...string literal is not properly closed by double quote...this is my java file
<%
String uname=session.getAttribute("username").toString();
String pword=session.getAttribute("password").toString();
java.util.Date dat=new Date();
int x=1;
try{
[code]....
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Jul 11, 2014
string literal is not properly closed by a double quote
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Aug 14, 2014
I have a Linux Server Debian 7 x86_64 Minimal With java version "1.7.0_65" installed..Its an online Game Server wich Players can join just like other Services.Every 10 - 15 minutes all the players get kicked from the server and get this messege: "internal exception: java.io.ioexception: an existing connection was forcibly closed by remote host"
The players can't join the server for 10 seconds and the server console doesn't show anything for 10 seconds.it doesnt show that the players even left! and when the players try to join they get htis messege: "same nick is already playing"
After 10 seconds everything will work and players can join again and server console say that everyone left and joined..But that happens again after 10 minutes and im losing lots of players because of this error.
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Apr 20, 2015
Basically I'm trying to compute the standard deviation for a set of numbers and I'm using previously know data to compute this. The data I'm working with is here (note all of this is fake as its for an assignment):
Id,First Name,Last Name,Quiz1,Quiz2,Quiz3,Lab1,Lab2,Assignment1,Exam1,Exam2
58136,Wade,Andrews,5,8,2,2,20,47,20,40
59759,Jacqueline,Simmons,9,4,1,16,13,2,82,41
28056,Frederick,Castro,8,0,6,3,6,29,53,63
15532,Annette,Myers,2,6,0,14,13,4,77,43
Next this is the code that I know is producing the error:
/**
* Pass in original data from files, and pass in computed grades as arraylist. this returns all of the standard deviations to be printed
*/
public static ArrayList calcStandDev(String data1[], ArrayList<Double> grades, ArrayList<Integer> averages)
{
double standDev = 0;
int j = 0;
//gets rid of first element in string array, makes processing MUCH easier
String[] data = Arrays.copyOfRange(data1, 1, data1.length);
[Code] ....
Look for the line with all the ***'s, it is producing the "java.lang.ClassCastException: java.lang.Double cannot be cast to java.lang.Integer".
The reason I dont undersand why its producing this error is because temp.get(i) should be a integer - averages.get(i) (is type double), I do believe automatic up casting is present here making them both a double then I multiply it by itself producing a double? I dont understand where the casing is occurring. And just incase you want the formula I'm using for standard deviation here it is:
((x1 - ave)^2 + (x2 - ave) ^2 + (xn - ave) ^ 2) / (n-1)
then squareroot above
Why I'm getting this error! I tried changing a few dataTypes but I just cant avoid exceptions being thrown everywhere .
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Oct 24, 2014
The purpose of this program is to import via keyboard Numbers.txt and calculate the mean and standard deviation to Results.txt.I am able to get the mean calculate but when I open the Results.txt the standard deviation is 0. I don't know what is wrong with my code, but I believe it has something to do with the scanner being close. Here is the error message i receive after inputting Numbers.txt.
java.lang.IllegalStateException: Scanner closed
at java.util.Scanner.ensureOpen(Unknown Source)
at java.util.Scanner.hasNext(Unknown Source)
at StatsDemo.main(StatsDemo.java:48)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at edu.rice.cs.drjava.model.compiler.JavacCompiler.runCommand(JavacCompiler.java:272)
Java Code:
import java.text.DecimalFormat; //for number formatting
import java.util.Scanner; //for keyboard input
import java.io.*; //for using files
public class StatsDemo
{
public static void main(String [] args) throws IOException
[Code] .....
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Sep 12, 2014
I need to create a simply application that would display the results of two dice thrown five times and the total of those results. This is shown below in the attached file.
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Attached below is also the code I have thus far.
(Attached below is both files: what it needs to look like, and what it currently looks like)
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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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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
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public class Socket {
public Socket(int port) throws IOException {
new SocketThread().start();
} }
public class SocketThread extends Thread {
protected DatagramSocket socket = null;
[Code] .....
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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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I am new to JSP !! and I'm developing a web-based chatting system using JSP and socket.
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[code]...
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