Passing Objects From Client To Server - Receives But No Return
Apr 30, 2015
I'm trying to pass an object to a server and then back again. The object gets to the server fine, but either the server doesn't return it correctly or the client isn't accepting it. There's not error's. The client just prints the object as null. Not really sure why, I looked at other examples and they seem to be the same.
Client:
public class main {
public static void main(String[] args) throws IOException {
String serverAddress = JOptionPane.showInputDialog(
"Enter IP Address of a machine that is
" +
"running the service on port 9090:");
Voter you = prompt();
[Code] .....
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Apr 27, 2014
My task is to make a mortgage calculator where the user selects which calculation they want the program to do via a menu. I got the menu to work and it keeps on looping until terminated so that's good. The starts when I want the user's choice (P, I or T) to be used in another method which will then execute another set of code (the calculation that needs to be done). I think passing parameters and return statements are what I need to use, but after reading and watching videos, I'm still not sure how to implement it into my program. For now, I want the user to input the letter "P" and then I want that information to be passed to the method, loanCalculator() where the if statement will make a decision to call the method, calcPayment and display the number 0 via the console. Once it can do that, I'll fill in the calculation methods with the proper code since I can at least navigate the user input to its associated calculator. It just keeps on looping the menu without going through the other methods.
import java.util.Scanner;
//Example of "big loop" in main to repeat using a No Trip (0,N) test first
public class Mortgage {
// constants
static double loanAmount;
static double interestRate;
static int term;
[code]....
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Oct 22, 2014
I am attempting to test a TCP Client and Server for an assignment I am doing in class. The goal here is to "test your client and Server applications by transferring (i) a file having 10,000+ lines (see supplied big-file1.txt having 12000+ lines), (ii) a file having 20,000+ lines (you may create one of your own from big-file1.txt, or obtain a large size file from the Google website at [URL] ...). Then, compute and display the total transfer time of the files at both of the sides separately (your choice in millisecond/second)."
I have created the TCPClient and TCPServer java classes, ran the server first and then the client, and using mathematical formulas to calculate the transfer time. Trouble is, I'm having trouble testing the client and server in the file area and not the area where I had to input a line, let the server print it, and then have the client eliminate the articles from the line. I need testing the file. Here is my code so far:
TCPClient:
package tcpclient;
import java.io.*;
import java.net.*;
public class TCPClient {
public static void main(String[] args) throws IOException{
// TODO Auto-generated method stub
String sentence;
[code] ....
How to fix the code so that the time in seconds does not output as 60 for both files and that the files go through the exchange?
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Apr 20, 2015
I have a program using Pipe line to exchange the infomation in the Client-Server model. Can I separate out main function and then put into Server main and Client main?
//PipeEchoServer
public class PipedEchoServer extends Thread {
PipedInputStream readPipe;
PipedOutputStream writePipe;
PipedEchoServer(PipedInputStream readPipe, PipedOutputStream writePipe){
this.readPipe = readPipe;
[code]....
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Feb 17, 2014
I have to develop a code in parallel which is implemented in sequential yet. How to add the server client relation in the program so that work can be divided into multiple clients.
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Apr 2, 2014
I've just recently started playing around with network programming in Java, and I've come up with a simplistic server than can handle multiple clients and return the IP and port each one is connected to (or I'm under the impression that is so). What I've been requested to do as an exercise by one of the programming teachers at my high school (I'm not in a class, this is my own time) is send a message from one client to the other through the ServerSocket so that it may "watch" everything going on. I'm not sure how to go about this at all.
EDIT : now it never seems to go the the else or else if statements...
That is now the main problem. It never, ever, goes past the first if statement, no matter what it is.
EDIT : Okay, I haven't changed a line of code but suddenly not a single if statement is working. They just stopped. The client simply hangs and I can't type anything.
Server
public class Server implements Runnable {
Socket clientSocket;
Server(Socket clientSocket) {
this.clientSocket = clientSocket;
}
public static void main(String args[]) throws Exception {
ServerSocket ssock = new ServerSocket(3480);
System.out.println("Listening on port 3480");
[code]....
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Sep 3, 2014
I have a problem on how to make my client to send the object to a server.
So I have one interface called "RMIInterface" and client "RMIClient" and server "RMIServer":
RMIInterface
interface RMIInterface {
public String getMessage(String text) throws RemoteException;
}
RMIClient
public class RMIClient {
[code]....
With this program I can connect to a Server with a Client, and print in Client console a message.But, how can I send message from a client to a server, and print that message in server console output?
make the simpliest example with sending a message to a server, edit inteface header code to public interface RMIInterface extends Remote, I forgot to add.
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Apr 6, 2014
I want to ask that, when a server listen to A port and it accepts a request from a client then the server accepts the request using accept method,but how does the server get the info about the client like wat is the port no and ip address of the client,I read a answer regarding this that Server never gets the port no of client only the ip address and it connects to client using a connection stream but as far I know from networking, a device must have the ip address and port no of the device it wants to connect to.
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Jul 22, 2014
So we have a Client and Server. Client opens a socket to Server, server initiates new Thread to handle the communication with client. Is there a way to be singnalled when there is input on socket, so I don't have to use infinite while loop solution?
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Jun 9, 2014
I have gf 4.0.1 and swing client. I want to get EJB over SSL. I've set all certificates. However, I can get it work only when client and server are at the same host. What I see in tcpdump when they are at the same host:
10.0.17.2.48524 > 10.0.17.2.3820: Flags [P.], cksum 0x378f (incorrect -> 0xf2b6), seq 399:756, ack 1085, win 273, options [nop,nop,TS val 347297976 ecr 347297966], length 357
13:01:26.334898 IP (tos 0x0, ttl 64, id 51559, offset 0, flags [DF], proto TCP (6), length 665)
10.0.17.2.3820 > 10.0.17.2.48524: Flags [P.], cksum 0x388f (incorrect -> 0x626d), seq 1085:1698, ack 756, win 273, options [nop,nop,TS val 347297977 ecr 347297976], length 613
[code]...
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Mar 10, 2014
I am looking to run Server and Client from two different JButton.
When I click on start Server button, the server starts to run but I cannot click on start Client button to start the client. Here the code for server:
Java Code:
public void actionPerformed(ActionEvent e) {
Client c = new Client();
c.run();
} mh_sh_highlight_all('java');
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Dec 28, 2014
I've been trying to create a server/client chat program, but I keep running into areas where I'm not really sure how to work it. I've run into a wall where my client just sits and spins instead of working. URL.... I can work out the dynamic parts later, I just want to understand the meat and potatoes of reading from sockets and writing to sockets (and how to do both at the same time).
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May 2, 2015
I'm trying to build a SSL mutual authenticating private server. I'm not sure what keystores, truststores, or certificates I need to accomplish this. I made keystores for both programs using:
keytool -genkey -keyalg RSA -alias selfsigned -keystore keystore.jks -storepass password -validity 360 -keysize 2048
The server starts up fine, but when I run the client they both give errors.
Server code:
System.setProperty("javax.net.ssl.keyStore", "CLA.jks");
System.setProperty("javax.net.ssl.keyStorePassword", "password");
SSLServerSocketFactory sslServerSocketfactory = (SSLServerSocketFactory)SSLServerSocketFactory.getDefault();
SSLServerSocket sslServerSocket = (SSLServerSocket)sslServerSocketfactory.createServerSocket(9090);
SSLSocket s = (SSLSocket)sslServerSocket.accept();
BufferedReader in =
new BufferedReader(new InputStreamReader(s.getInputStream()));
[code]...
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Apr 6, 2014
It's an RMI program that has to be able to return the mean, mode and median of a set of numbers.It's composed of 4 classes; a client, an implementation class (with the math), an Interface, and a server class.
import java.rmi.NotBoundException;
import java.rmi.RMISecurityManager;
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Scanner;
import java.io.*;
[code]....
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Dec 6, 2014
So i wrote this text to try and create a simple chat program that does the following: Prepend names to messages, announce entrance and exit of chat, display user list, and share a whiteboard.So far the Server seems to be working but the Chat Client is throwing errors at me left and right..
CURRENT ERROR:
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.
C:Windowssystem32>cd..
C:Windows>cd..
C:>Usersjaydesktopchat
'Usersjaydesktopchat' is not recognized as an internal or external command,
operable program or batch file.
[code]....
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Mar 4, 2015
I am creating a server that stores application updates. When the client connects the server send the update. The server is sending the file but the file is not complete, i.e, if the file is 317kb,its send 117kb. Below is the code I am using :
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
public class TestFileServer {
[Code] ....
What could the problem be?
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Oct 28, 2014
Whether I pass primitives or objects the original value does not change. Is this expected result?
Java Code:
public class Class {
public static void main(String args[]) {
int x=3;
doItPrim(x);
System.out.println(x);//3
Integer i=new Integer(3);
[Code] ......
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Mar 20, 2014
We are learning about how to pass objects into constructors. In our class, we made this following code:
public class InventoryItem {
//fields
private String description;
private int units;
//Add New constructor
public InventoryItem(InventoryItem some_object) {
description=some_object.description;
[Code] .....
As you can see the object of the same class is passed as the argument. Inside the constructor, our teacher did
some_object.description
This constructor, from my understanding, copies the description field and unit field to an object to the new object of class. Meanwhile, here is the demo class.
public static void main(String[] args)
{
//Create object
InventoryItem item1;
item1=new InventoryItem("hammer",20);
System.out.println("Item 1: ");
[Code] .....
Over here, my teacher uses :
.getDescription
My problem is that in the constructor of the first class I showed, why didn't he use
.getDescription
method instead of this
.description
May I know what is difference between these two. If I use .getdescription that would return the value of a field from that object too.
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Jun 14, 2014
What is the best way to send an arrayList from the server to the client? ObjectInputStream and ObjectOutputStream?
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Apr 3, 2014
I'm working on an assignment right now which involves passing a variable series of numbers to the Server to be sorted into the correct order and returned to the client.
So far I have it connecting to the server and asking for my numbers, and I am entering each number and pressing return, and it is accepting each number individually.
One (smaller I think) problem i'm having is with the client code, specifically the while loop.. I've tried to code it so that when I enter a full stop ('.') the program will stop asking me for more numbers and move on to sending them to the server.. but instead it just crashes giving an error.. heres an example
"Enter a number: 1
Enter a number: 3
Enter a number: 2
Enter a number: 1.
java.lang.NumberFormatException: For input string: "1."
at java.lang.NumberFormatException.forInputString(Num berFormatException.java:65)
[Code] ....
Here's the client code in full
package numberSortprogram;
import java.io.*;
import java.net.ServerSocket;
public class NumSortClient {
public static void main(String[] args) {
InputStreamReader is = new InputStreamReader(System.in);
[Code] ....
The big problem that I have is figuring out how to send the sorted array back to the client..
So, what im trying to get to happen is-
-Client is asked to enter numbers
-Client enters series of numbers into an array
-Array is converted to a string and sent to the server
-String is then split into an array of strings and sorted using compareTo (don't know if this is the best way?)
-Sorted array is sent back to client and displayed.
fyi this is making use of streamsockets..
All of the rest of my code is below:
package numberSortprogram;
import java.io.IOException;
import java.net.*;
import java.util.regex.PatternSyntaxException;
public class NumSortServer {
public static void main(String[] args) {
int serverPort = 4444; // default port
if (args.length == 1 )
[Code] .....
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Jan 22, 2015
I want to send a message to a specific client in a server. This is my code and what I tried(I have only given you 3 classes in which I believe I have the problem).
TextClient:
import java.io.*;
import java.net.*;
import java.util.ArrayList;
import java.util.Scanner;
import java.util.concurrent.TimeUnit;
public class TextClient {
public TextClient() {
[Code] .....
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Sep 27, 2014
I've been provided a code skeleton for what must be done, but despite my best efforts to make things work, I'm coming up dry (obviously, due to a lack of knowledge.) One thing that might work is if I knew how to debug this type of application, line-by-line, to see exactly what is going on. Obviously, it's easy enough to debug the client part, but moving over to the server part, I haven't been able to figure that out (I'm using Eclipse.)
Anyways, here's the code I've got so far:
Client.java:
import java.io.*;
import java.net.*;
[code]....
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Mar 1, 2014
I have a https connection from Client to Server and a malware in client. The malware modifies the message and compromises its integrity. I am using a proxy to check the Integrity of the message after the malware has changed the message and before sending it over the internet to the server.
Now, How can I check the Integrity of the message (Sure that it has not been modified by any Man in the Middle) for the second half of my communication channel(Which is from Client to the Server over the internet).
I see few conventional approaches of CRC or Checksum will work. But I am looking for some non traditional or upcoming approaches.
Ideally SSL Data shouldn't be able to be decrypted by any MIM. But my assumption is that any Protocol is subjected to attack and compromised in real world and few recent studies are proving that https is breakable. Thus, I am trying to perform a What if analysis? On the client side, lets say malware is not more powerful than just modifies the transaction amount and destination account number in a typical online Baking transaction.
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Jan 16, 2014
I am try to make an Java application using swing, to play the video from server, client can only view the video.
I am new for using Media Work in Java & using VLCJ too,
I have try by using "vlcj-master".But it showing .dll file missing error on native method..,
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Apr 18, 2014
I am currently writing two java classes (client and server). The client takes an input number form keyboard and sends it to the server. The server then multiplies this number by two and sends it back to the client. The numbers should also be printed to screen along the way, for example if I input the number 3 I should get
"From Client: 3" "From Server: 6"
They should continuously do this unless a negative number is received by the client, say for example the number -3 is sent to the server and it returns -6.
The code I have for the two classes so far is:
import java.io.*;
import java.net.*;
import java.nio.ByteBuffer;
import java.util.Scanner;
class Client {
public static void main(String args[]) throws Exception {
DatagramSocket clientSocket = new DatagramSocket();
[Code] .....
Currently, when I run the program all I get is an output of the number first entered. I am aware it requires a loop but I don't know where and what the condition should be.
Also if I wanted to adapt this so that it would take the integer from client and subtract two at the server and return to client who sends back to server to keep subtracting two unless it reaches a negative number at which point the client will terminate the program - how might I do this.
I do realise there needs to be a while loop in the above code, but I wanted to test it sent the number from client to server and its not doing it. All I get is a print screen of 'enter number' and then the number I enter.
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Aug 9, 2014
I had some questions about a theoretical java program. Say you had a java program on a linux server/pc that referenced a folder on that server. And say you had a Client PC (Windows) that had a share folder to that java program.
If that windows client PC tried to run the program would it run (with a GUI if it had one) and would the main directory of the java program still be on the linux server or would it be on the windows computer since that is the computer that is running the program?
Basically I have a program I am trying to find the best way to run it remotely on a windows computer but it references files on the linux server it is located at and needs to put files it creates there as well. I am just trying to make sure I understand my theory here on how the program will run if it IS run remotely.
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