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Java Network Q&A
Java Network Q&A » Client » Client 1 

1. No stack trace generated on client site for NullPointerException?

I've been learning Java for about a month now, and not very familiar with a client/server situation like this one. Basically I ran into a situation where our client java software (GUI) ...

2. Implementing client - masterserver/slaveserver application java

We have a string processing service (c++, uses stdin/out for in/output) that has different layouts, each layout runs separately (eventually will run on separate machines), each layout takes time to load, ...

3. how to tell if VM is running in server or client mode?

The Java hotspot vpm can be run with -client or -server argument. If neither is specified then it chooses one according to some rules. Is it possible to tell whether a running ...

4. Passing coordinates from a java client to a java server

Firstly I know coordinates is probably the wrong terminology? I'd assume i'd simply be passing the x and y variables, but coordinates describe it better I feel. Now I need to have ...

5. Java client and server problems

I've editted this post based on recommendation by a fellow user. My specific problems are as so: Currently when I run, it loads up a map with a player on it, you ...

6. Why won't my server and client I coded in Java work?

My server keeps getting this error when I run the client:

Exception in thread "main"
    at Source)
    at$BlockDataInputStream.readInt(Unknown Source)
    at ...

7. My basic java server accepts 3 clients instead of 2

Okay, this sounds simple, but I tried all the simple things and it still doesn't work properly.


public class MyServer{
    public static void main(String[] args) throws IOException ...

8. My java server stops in the middle of its code

For some reason my server stops running in the marked area of my code, and I can't figure out why.


public class SlickServer{
    public static void main(String[] ...

9. Can someone help me speed up my netcode in Java?

Okay, So I'm working on a game (like not even alpha yet) and it's suppose to be a 1 on 1 fighting game where one person hosts the server and the ...

10. Anyone know of an FTPS client that runs on java 1.3?

I know 1.3 is old as dirt, but I don't have an option of doing a jvm upgrade at this point.

11. Quick Java LinkedList problem

Basically I'm rather new to Java and I have a problem with understanding a line and getting it to work. Heres the line of code:

LinkedList<ClientWorkers> clients = SingletonClients.getClients();
Heres the procedure its in:
ClientWorker(Socket ...

12. Opinion of a Naive way of implementing load sharing for a server on the client side

I was thinking about client sharing for a server that could be accomplished by client side execution with little or no help from the severs end, and came up with this ...

13. Stopping a parallel java task with ant

I am developing two java programs that run in separate VM's that have a typical server/client relationship. Using ant's parallel/sequential tasks I've been able to get ant to run the server ...

14. readobject method throws ClassNotFoundException

I'm trying to pick up Java and wanted to test around with Java's client/server to make the client send a simple object of a self defined class(Message) over to the server. ...

15. interaction of client and server in java

write a program in java which interact with client and server

16. Shared resources in a Java project for server and client packages

I have a Java project that has both server and client packages. In addition I have a library package. I use eclipse and have put everything in a single ...

17. How can i test the interactions between 2 or more clients on different VMs?

I need to test the interactions between 2 ore more java clients in a complete end-to-end test. Without the GUIs ideally it should be something similar to (Junit syntax):

@Test public void EndToEndTest(){ ...

18. Java: How to make clients detect server on network?

During my years at the university I had a personal project of making a simple chat program in Java, using TCP sockets. The project was only for educational purposes. One thing I ...

19. Network sent Vector only updates once in client?

Okay, so I'm trying to send a vector of objects from server to client. the clients take control of one object from the vector and send it's x and y to ...

20. HowTo Unit Test Client Server Code

I'm currently writing a Java Client Server Application. So i want to implement two Libraries, one for the Client and one for the Server. The Client Server Communication has a very ...

21. Client computer name in java

I want to find client computer name in java. My applciation runs in intranet. so i am using below code

   public String findClientComputerName(HttpServletRequest request) {

22. Simple Java client and server not interacting properly

I can't understand why the code below doesn't work. The client sends a message to the server, and the server prints the message to standard output. Code for the server:

import ...

23. SAML SSO client, Test simulator SAML Provider/Server

SAML, SSO is a new learning in my project. I don't have enough time to experiment to find the correct tools/APIs. Requesting you to help. I need to implement SAML Client (on ...

24. How to get MAC address client side with js,flash,java or etc. with crossbrowser method

How to get MAC address (or something unique for each pc -at least standart user knowledge level-) from client side with js,flash,java or etc. with crossbrowser method? You probably know when we ...

25. Client Server Programming in java

I am just working on my assignment of client-server and found an program online of a as:


public class MyServer{

    public static void main(String [] args){

26. Client server application java

I learned that Server application makes a ServerSocket in a specific port,

ServerSocket ServerSock=new ServerSocket(9000);
and client makes a socket connection to the server application,
Socket sock=new Socket("","9000");
So client knows the Ip address and ...

27. make a client server java application

I am trying to make a java application in a client/server way. The client is a GUI in SWT wich display data from the server. The server is connected to a database. Ok, ...

28. video transfer from client to server in java

how to transfer a video from server to client..plss tell me d whole procedure from d scratch...

29. CVS client java programming - how does cvs server interpret a "local directory" argument

I'm using CVS for a java database application Having learned basic CVS using a command line terminal, i want to emulate the terminal commands in CVS client mode using java to send ...

30. SSO between java client and iis server

I am trying to implement java httpclients for a SSO iis server. I googled it for hours but could not find a good explanation or not understand. What should i do ...

31. Adding IPv6 support for JCIFS client

I have client written using JCIFS library. Now I need to support IPv6. But JCIFS does not support. What direction should I take please guide me.

32. making single client and server

I have written a client server program:

  class verify {
  public static int serverPort=998;
  public static int clientPort=999;
  public static int buffer_size=1024;

33. Run application both as server and client

I want to make my pc both server and client. This is my code

class tester {
static int pos=0; 
 static byte buffer[]=new byte[100];
   static void Client() throws Exception {

34. How to cause server to serve slower download to client ( like all this direct download sites )

I'm using java tomcat as backend end apache from end for static files with mod_js in between I like to give the users slow and fast options , fast will be ...

35. Create an OPC client with OpenScada UTGARD

I´ve connected a PLC to Matrikon opc universal server, now my task is to connect the OPC server to a client based in Java. Im using jinterop libraries and i think ...

36. Client Server Program stuck after loop?



import javax.print.PrintService;
import javax.print.PrintServiceLookup;

public class GetFileServer implements Runnable {

    public static final int SERVERPORT = 4444;

37. Client-server application null pointer exception

I am working on a mini-project which consists of doing a client-server chat application. The application has a GUI and my problem is that I am trying to get the information ...

38. Client Server Program String leak?

My Server Program:-


import javax.print.PrintService;
import javax.print.PrintServiceLookup;

public class GetFileServeredit implements Runnable {

    public static final int SERVERPORT ...

39. java: merging a server into the client

i have a very simple turn-based online game in java. the client talks to the server using normal java sockets. now in order to play the game offline as well, i want ...

40. How to store server password in Java client for later reconnects?

I have a client application that connects to a server over a secure/SSL socket. The user is required to log in when the app starts. Right now I have ...

41. XML-RPC - Throwing Exceptions from Server to Client in Java

It is my first time posting here and I could not find the answer to my question during a search so lets see if I can explain myself correctly. I am using ...

42. Error on customers computer

I have a java client server program that works fine on a half a dozen computere but is causing a NegativeArraySizeException on site. This is the code

location = message.indexOf("last");
location += 5;
end = ...

43. my code hangs but when i debug it it never hangs

i have a java code that SOMETIMES hangs when i run it.Its a put command that puts through sockets( and input stream etc a file from a server to a client) ...

44. System.getProperty("catalina.base") There can be scenario where client may use any other server

I am reading a properties file from Tomcat\conf\ directory using

String demo = System.getProperty("catalina.base") 
    + File.Separator + "conf\";
This is working perfectly fine with Tomcat. But, there can ...

45. problem with server and client , working on my machine not working on another

hello guys i have designed a server client which transfers data through sockets. Everything is ok when i run it on my machine it works 100% of the time. When i ...

46. how to communicate between client and server in java

I have a chat program. Now the code works for communicate between client and server via command line. But it gives an exception ( Socket is closed) while running. Please help ...

47. How to verify from server that client code hasn't been modified

I have a java server that communicates with a java client via json-rpc. The client is supposed to report internal stats to the server which modifies the servers behaviour. ...

48. How should I run a Server/Client Code?

i just started writing my first Server/Client code and its a simple chat program , but i dont know how should I run the Code ! there is a .class ...

49. How to broadcast in java network

Its my first time programing network in java. I was looking for a way to send to somehow broadcast to all nodes in the whole networking. To let them know of my ...

50. How to have a different instance of the handler/processor for each client in Thrift?

I know that the handler run in a different server thread for each client, but how can I have one instance of the handler for each client. I'm writing my server in ...

51. How to - Flex client side and Java as Server side

Since I'm developing a multiplayer card game for Facebook using Flex as client side and Java SE as server side, I wanted to know how do I actually make the connection ...

52. Need a recommended place to host my Flex client and Java server

Please let me know of a good free place to host my multiplayer card game for facebook which the client side is a FLEX web application and the server side is ...

53. What can I do to avoid a NullPointerException?

I am trying to authenticate user by sending a key and a random number from the client to the server. My code is not displaying me the response from the client. I ...

54. What is the difference between the Java Client VM and the Server VM?

Possible Duplicate:
Real differences between "java -server" and "java -client"?
what are the technical differences between starting a java program with -server and with -client flag? Thanks! ...

55. java client server serialization problem

hi i am working on a client server programme with containing some special functions like sending private message, show online list etc. so i know i must use serialization and first ...

56. Client Server Apps+java

I have a java requirment contains both client and server side program.

Server side

Server program frequently check the data base and checks if a new order came, if order came it check ...

57. Server Client Program in Java

I'm implementing a program where the controller(server) calls the agent(client) periodically and sends it IP address.

public class Controller {
         static int discoveryInterval;

58. Is there some client server system java programs I can look at?

I'm currently doing a project where I'm going to build an application (created in Java) alongside a database. So this will be client server system i'm developing. Part of my project ...

59. Better solution for Client/Server Socket-System

I have a Server and clients(1000) which the server communicates in every sec. I am creating a single thread on the server for each Client. What I want to know: Is it ...

60. Red5 - Invoking client methods from application server independantly

How would you invoke a client flash method from application server in java applicationadapter. I know how to invoke client flash methods from application server when adding this to flash client:


61. Apache xml-rpc client and server implementation

I have been trying to figure out how to implement a simple xml rpc server and client with apache xml-rpc ( but i haven't been successfull. I implemented a server and ...

62. Java Client Server Model

is it possible to send a stream of UDP packets let say 15 packets of size 1500 with each packet time separation is 5 seconds or it can me some ...

63. Creating Java Client for CMIS-based server

I am still new in CMIS subject , and I am still searching learn about that, What I want to do is to create a Java client that upload report ...

64. A "Client - Server" performance issue

I have a "Queuing Theory" problem where following are to be done:

  • Develop a CLIENT to send continuous packets of fixed size to SERVER at fixed rate
  • SERVER has to queue these packets ...

65. RTMPS , implementation not getting hit from client side

I m trying to implement rtmps on my red5 server. i have added the certificates i.e imported them to a key store and have uploaded them on the server. have enabled ...

66. Which is the most secure, reliable and scalable framework for server client applications ?

I am working on a android project where the android devices are client and server is required to build in a secure, reliable and scalable framework(Java based). So please suggest me ...

67. Java client server code

Can you help me to check whether the logic of my ack server and ack client is correct or not? The client keeps sending ack to a server and when the ...

68. JXTA client - server

I would like to implement a client-server architecture using JXTA. Also the configuration of the server part will be 3 - tier. Does anyone know a good place to get this ...

69. Can a client also be a server, socket/serversocket

Hi, i have created my own messaging program which entails basically having a application with a serversocket listening for connections and then does it's thing when it receives a connectin from ...

71. Client Server problems in java

I want to sent a .dat file from the server to the client and have the client put it in an array and display it. My problem is on the server ...

72. Java Server Client application Signing the client jar

Hello, I'm doing some research in to Java security, and I have a question. In my line of work I find from time to time client applications written in java (so ...

73. Java client server issues

Hello everybody, Maybe someone from you can help me. I am writing a server/clients in java, and i need to store the request IP addresses from the clients and respond only ...

74. how to write two server programs handling many clients

There should be some way to detect the the primary is still up or is it down? Your secondary server should come up once the primary is down. And the connection ...

75. Client and Server on different machines

Dear all, I've just developed a small client/server application using RMI. At the moment both the client and the server reside on the same Unix box and every thing is fine. I first fire the rmiregistry, followed by the server and the client. Now I want to move the server to a separate Unix box. Which sequence should I follow to ...

77. About client server tech

Hello guys WE are trying clients server techno. using SWING. in Doing entries. Can any body tell me that how to get back the all errors from server's side to clients, so that they can know about the status of entry. currently i have designed it in way that it will throw errors on serverside. Can you help me out? Thanks ...

78. Passing an object back and forth between Client and Server!!!

hi folks, i am trying to pass an object through a socket connection. i have created a server socket that reads an employee object created by a client. So the client creates an object in a different machine and sends it to another server machine which it reads and prints. this is just for my experience. Now what i am seeing ...

79. Client server Starting Order?

Here's a funny one..... imagine this if you will..... I have an RMI server object it 1. starts a thread to broadcast it is alive 2. Registers with the Registry 3. Waits for method calls I have an RMI client it 1. Has a thread which detects bcast packets 2. Instanciates an RMI client and does Named.lookup(address, object) every time it ...

80. Output on server instead of client !!

I am running the Sun's RMI introductory bundle of programs on my machine. Essentially - 1. Defined a server class with a remotable method sayHello(). This method is in a class that implements the Remote interface. 2. Started the orbd 3. Created the skeleton and the stub through rmic 4. Called the sayHello() from a client. All the code is exactly ...

83. App won't run when client is on a different machine than server - $donation

Ok, Im trying to get this fairly small and simple RMI application to work. Im at my wits end right now and after many hours of fiddling, I seem to be no closer to the solution. Whoever is the first to suggest a solution to this problem can choose their favorite open source group which will receive a $20 donation. Otherwise, ...

84. "Push" to the remote client Java application from server-side

Hi, I know that the following "pull" scenario works, it is a form of polling, and fits into the standard request/response communication of a servlet web application: 1. Java Applet or Application on the client responds to the user clicking on a JButton. 2. The Applet/Application communicates over the intranet to a specific servlet, MyServlet, sending it the appropriate parameters. 3. ...

85. communicate non java client with java server side components ?

Basically you just open streams and send bytes. Each side has to agree what the bytes mean, so it takes some planning. I did a Java search engine talking to Perl program clients and sending binary data over permanently open socket connections - the receiving side had to know when a block of data was complete so each communication started with ...

86. JDK versions on web server and client machines

The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - ...

87. server as a client of anthother server

88. Count of the clients accessing the server

Hi I wouldn't see this as being a 'java' thing since most wbservers logs can be run through a stats program and give you all this info. BUT I might look at this in the following way: Create your own class that is 'called' on each page. It can track the IP/sessionID and keep a count of 'unique' hits, and then ...

89. Client - Server

Travis is correct however You should think of it in terms of "software". Server is software(program) running on some computer that provides services to other software/programs. Often the computer that a server software runs in is reffered as "server". For example Web "server" is software that is running on some computer and awaits and accepts calls from "clients" and serves them ...

90. Client pull and Server Push

A client pull is when a client program solicits data from the server. A server push is when a server sends unsolicited data to a client. An example of a server push would be an application where a client registers interest in a particular data item (lets say a stock symbol) and the server pushes data (such as stock purchase and ...

91. Client Side vs. Server Side Validation

I have a lecturer at my Uni that is taking us for 'E-Commerce'. This lecture is teaching us to validate data on the client side using java-script. I want to raise that validation should be done on the server side so we shouldn't be learning this as java-script can de-enabled and 10% browsers dont have java-script enabled (W3C, 2005). Is there ...

92. Refresh Client from Server

93. Difference Between Client side Redirect and Server Side Redirect

Forward and Redirects: The forward and redirect operations both replace content. The current page or output stream is terminated, and is replaced with the output of the specified page. Forwards: Both and RequestDispatcher.forward() are what I refer to as "server-side" redirects. The redirect operation is performed in the server side, and the browser is unaware of the change. If page1.jsp ...

94. Edit and Save word document on server from client machine

Hi all, I have a JSP application which runs on Apache Tomcat Server. A JSP page lists the word documents(procedure documents) which reside in a specific directory say c:\temp on the server. My question is will I be able to edit and save the word document on the same server directory with same file name, by accessing the document from the ...

95. compiling a client server application

i have a client server application in sockets. the client side has 5 classes. and the server side consists of 4 classes. now i want to compile them through the dos shell using the javac command but it wont work there is no problem with the code as it runs through the jar file. my friend told me to use command ...

96. Client / Server

Hi I have a client/server application. The server serves to several clients at the same time. A client can close the connection with a special command. But i want that the connection is closed automatically by server when a client is not active for 10 second is. How can i implement this? Any help would be appreciated. Cheers

97. Client / Server Question

Hello everyone! Ive got a question for you. I am writing a SalesmanClient and a SalesmanServer, everything is working great so far, but I am a little stuck now. I have a GUI that pops up when I run the SalesmanClient that lets a user enter sales data, change sales data, read a text file, write a text file, write objects ...

98. Checking Server is Up or Not from Client

Automatically means... The Client need to check on a regular interval whether the server up or not.. Is there a possible solution for that.. Because this is a thick client application, only when it save the data or communicate to server it will get to know the status of server. Otherwise you can continue working on locally means client side Regards ...

99. Client Server Applications in Java

100. client server program

Howdy Gordo; I can point out a few things off the top of my head. 1) check your variable scope -- for example, you're trying to close the socket 'connection', in your closeConnection, but connection is a local variable from another method. Make connection an instance variable. 2) It looks like your fundamental approach *is* right, though -- get streams from ...  | Contact Us | Privacy Policy
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