Java Discussion Boards

Re: user authentication

Richard MacCutchan15-Mar-10 22:29

Richard MacCutchan

15-Mar-10 22:29

Kunalpuranik wrote:
i know the class have to implement serializable interface.

This interface is for saving and restoring an object's state, it has nothing to do with client/server communication. You will need to use some socket implementation to achieve your objective.

txtspeak is the realm of 9 year old children, not developers. Christian Graus

Re: user authentication

Kunalpuranik16-Mar-10 0:32

Kunalpuranik

16-Mar-10 0:32

hey,i know the socket programming.but the socket programming is just to establish a link between client and the server.

i also know how to transfer strings between client and server as i have developed a chat application.

but what iam asking is how to transfer the object of my client class to my server end..

and the reason ive not written the code is because i dont know how to implement and thats why iam askin.
and if u want i can post my simple client server chat application code here.

Re: user authentication

Richard MacCutchan16-Mar-10 3:30

Richard MacCutchan

16-Mar-10 3:30

Kunalpuranik wrote:
socket programming is just to establish a link between client and the server.

Well it's a bit more than that.

Kunalpuranik wrote:
how to transfer the object of my client class to my server end.

The same way that you would transfer anything, convert it to a byte stream and squirt it down the socket.

txtspeak is the realm of 9 year old children, not developers. Christian Graus

Re: user authentication

David Skelly16-Mar-10 3:39

David Skelly

16-Mar-10 3:39

Richard MacCutchan wrote:
This interface is for saving and restoring an object's state, it has nothing to do with client/server communication

Well, strictly speaking he's right. If you want to send an object through a socket, the object must be serializable. If it isn't serializable then you have to convert its state to a serializable form (e.g. by invoking defaultWriteObject from ObjectOutputStream) before you can send it through the socket.

Think about it: the very act of sending an object from the client to the server involves saving its state at one end of the communication, and restoring it at the other.

Re: user authentication

Richard MacCutchan16-Mar-10 4:15

Richard MacCutchan

16-Mar-10 4:15

True, the shouting sent me veering off course. Hmmm | :|

txtspeak is the realm of 9 year old children, not developers. Christian Graus

Java3D

java3dArtist15-Mar-10 0:03

java3dArtist

15-Mar-10 0:03

Hey Guys,I am new bie to java3d.I want to know that am I on right message Board.Or this one is only for core java.
So,only after I can proceed with my questions.

Java3DArtist

Re: Java3D

Richard MacCutchan15-Mar-10 0:27

Richard MacCutchan

15-Mar-10 0:27

You are on the right board, but I do not know whether you will find many answers here. Java3D is a subject that not many people seem to be familiar with.

txtspeak is the realm of 9 year old children, not developers. Christian Graus

Importing and parsing a wsdl 2.0 definition,in java

userkm14-Mar-10 12:43

userkm

14-Mar-10 12:43

I amworking n importing a wsdl and displaying the methods in wsdl2.0 file in jave any ideas on this will be appreciated

Fill And Post Method to Web page

darkimmortalbora11-Mar-10 9:34

darkimmortalbora

11-Mar-10 9:34

Hi I'm tring to track my packages with my program..
I should fill a textbox called barkod with a value .. then click the button in the

website : PTT Genel Müdürlü?ü-General Directorate of Turkish Post

Trace Registered Postal Items
_____________________
|___BARCODE NUMBER___| BUTTON

but I couldn't do it, the code still returns the source codes of the main page..
what should I do ??? =((((

int ch;
		 URL url;
		 url = new URL("http://www.ptt.gov.tr");
		// HttpURLConnection httpConn = null;
		 String page;
		 
		 HTMLDocument myDoc = null ;
		 myDoc=(HTMLDocument)url.openConnection();
		 HTMLInputElement barkod = (HTMLInputElement)myDoc.getElementsByName("barkod");
		 barkod.setValue("RJ464842336GB");
		 HTMLInputElement buton = (HTMLInputElement)myDoc.getElementsByName("Sb22");
		 buton.click();

Side scroller

alexwilliams211-Mar-10 8:55

alexwilliams2

11-Mar-10 8:55

Hey,

Anyone have an example of a J2ME 2d side scroller game code i can look at?

Thanks

clear screen in java?? [modified]

AmbiguousName11-Mar-10 8:05

AmbiguousName

11-Mar-10 8:05

hello guys.....have you been able to find a method which could clear the screen in java?? Can we try, putting in a loop, something like

gotoxy(i,j);

where i,j are rows and columns respectively and then printing a balnk??

modified on Saturday, March 13, 2010 4:37 AM

Re: clear screen in java??

Richard MacCutchan13-Mar-10 0:23

Richard MacCutchan

13-Mar-10 0:23

Do you mean in a console or swing application? If it's swing then you have total control of what is drawn to the screen. In a console app there is no concept of a window.

txtspeak is the realm of 9 year old children, not developers. Christian Graus

Re: clear screen in java??

AmbiguousName13-Mar-10 1:29

AmbiguousName

13-Mar-10 1:29

yes...i wanted it on a console....im trying hard to find this out but still, u know. I have read somewhere that we can use System.exec("cls"); but that too is not working.

Re: clear screen in java??

Richard MacCutchan13-Mar-10 10:02

Richard MacCutchan

13-Mar-10 10:02

I am not sure this is possible from Java. "cls" is an internal 'MSDOS' command so can only be run from an invocation of CMD.EXE. However I do not think that this will do what you want. Take a look at Runtime.getruntime().exec() for further information.

txtspeak is the realm of 9 year old children, not developers. Christian Graus

Prob in MultiTextures

002comp11-Mar-10 0:05

002comp

11-Mar-10 0:05

hello Friends
I am using java3d Library.In regarding to that I am creating a scene with Multitexture.For that I am using Combine Mode,SetCombineRGBSource function.But I am not getting the full description of SetCombineRGBSource function,specially its parameter.

Is anyone aware of all these?

Thanks & Regards
Yogesh Sikri

Allow applet access to printer - once and for all

Klazen10-Mar-10 11:19

Klazen

10-Mar-10 11:19

Hey all,

I'm having trouble getting an applet to use the printer. Every time, it pops a message stating "The applet has requested access to the printer. Do you want to allow this action?" I check yes to an option underneath stating to always allow access, however, it seems that there is a lack of communication going on here, because the same message pops up next time. I've read that this can be fixed by adding this line to the java policy security file (java.policy):

permission java.lang.RuntimePermission "queuePrintJob";

But that solution doesn't work well for me, because I can't have everyone that uses my applet change their security files to avoid the annoying popup. The applet is signed, however, it's print method is being called directly from javascript and so I think there may be a bit of security tightening going on there causing the problem. Is there a checkbox or a setting somewhere I can have my users set, or is there something I can do on my end?

Re: Allow applet access to printer - once and for all

Richard MacCutchan11-Mar-10 1:46

Richard MacCutchan

11-Mar-10 1:46

The problem here is that applets run in the browser, and browsers are not allowed access to system resources without the express permission of the PC user. Otherwise their systems could be compromised by webpages changing things without their knowledge. I don't think there is any way round this issue.

txtspeak is the realm of 9 year old children, not developers. Christian Graus

Re: Allow applet access to printer - once and for all

Klazen12-Mar-10 13:29

Klazen

12-Mar-10 13:29

True, which is why there is a security policy file, which prevents access as the default. However, you can get around it by adding that line to the file. I was wondering if there was an easier way to change it, rather than editing that policy file by hand.

Re: Allow applet access to printer - once and for all

Richard MacCutchan12-Mar-10 21:53

Richard MacCutchan

12-Mar-10 21:53

Klazen wrote:
I was wondering if there was an easier way to change it

Not that I am aware of; and remember it would still require every user of your applet to change their own system.

txtspeak is the realm of 9 year old children, not developers. Christian Graus

Re: Allow applet access to printer - once and for all

RB Chowdary23-Feb-11 19:51

RB Chowdary

23-Feb-11 19:51

Hello Klazen,
by seeing your post i am sending this Qus.

if you dont mind can you provide the code for printing the file from applet.
Please help me............. Confused | :confused:

Re: Allow applet access to printer - once and for all

Andrew Thommo23-Feb-11 23:24

Andrew Thommo

23-Feb-11 23:24

> The applet is signed, however, it's print method is being called directly from javascript and so I think there may be a bit of security tightening going on there causing the problem.

You are correct. Wrap the call in a doPriviliged() method and it should work (in a trusted applet) without further intervention.

Messing with policy files is not something I would recommend even for development purposes.

Re: Allow applet access to printer - once and for all

Marc Schabb4-Jan-12 7:14

Marc Schabb

4-Jan-12 7:14

We tried this fix and it seems to be causing further problems. Our implementation is:

try {
    final Doc doc = new SimpleDoc (docBytes, javax.print.DocFlavor.BYTE_ARRAY.AUTOSENSE, null);
            AccessController.doPrivileged(new PrivilegedExceptionAction() {
                public Object run() throws PrintException {
            DocPrintJob printerJob = selectedPrinter.getPrintService().createPrintJob();;
            PrintRequestAttributeSet aset = new HashPrintRequestAttributeSet();
            printerJob.print(doc, aset);
            result.setStatus("SUCCESS");
            return null;
                }
            });
    }
    catch (Exception e) {
        e.printStackTrace();
        result.setStatus("FAILED");
    }

We're using the doPrivileged call with PrivilegedExceptionAction so that we can report the failure to the server to be reported. The problem is we are now seeing in the production logs that a small percentage of the print jobs fail with PrivilegedActionException, which we never saw before. We have not been able to reproduce this in our test environments, so in fact we don't really know whether the previous versions were failing or not - maybe we're just seeing the exceptions in the logs now, but they were always there.

prevent multiple instances of same server over the network

A-MEN10-Mar-10 6:40

A-MEN

10-Mar-10 6:40

import java.io.*;
import java.net.*;
class EchoServer
{
public static void main(String args[]) throws Exception
{
String clientstr;
String fwdstr;
ServerSocket ssock = new ServerSocket(5678);

while(true)
{
Socket conn = ssock.accept();

BufferedReader inFromClient =new BufferedReader(new InputStreamReader(conn.getInputStream()));
DataOutputStream outToClient =new DataOutputStream(conn.getOutputStream());

clientstr = inFromClient.readLine();
System.out.println("Input from the Client: "+clientstr);
fwdstr = clientstr+ '\n';
outToClient.writeBytes(fwdstr);
}
}
}

this is an echo server..i would like to know how could i make sure that multiple instances of this server is not running elsewhere on the network??? please help..

Cross-post

Kristian Sixhøj10-Mar-10 7:01

Kristian Sixhøj

10-Mar-10 7:01

Please do not cross-post[^] your questions. One post is enough.

Kristian Sixhoej
"You can always become better." - Tiger Woods

printf() help??

AmbiguousName9-Mar-10 7:49

AmbiguousName

9-Mar-10 7:49

hello guys....having a little problum in printf() function in java. I want to show data from ArrayList in a tabular form but unable to find proper examples of printf() function.Lets suppose each record in ArrayList consists of following
1) name
2) address
3) balance
How do i do this??......thanx for ur help

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