ObjectInputStream+CipherInputStream hang
I've started a simple client-server app and had communication working fine untill I tried to add encryption.
Here's the faulty code with info on object initialization
// init in and out cipher
outCipher = Cipher.getInstance(algorithm);
outCipher.init(Cipher.ENCRYPT_MODE, key);
inCipher = Cipher.getInstance(algorithm);
inCipher.init(Cipher.DECRYPT_MODE, key);
// create ObjectInput/Output stream
cipherOut = new ObjectOutputStream(
new CipherOutputStream(socket.getOutputStream(), outCipher));
cipherIn = new ObjectInputStream( // <--- HANGS HERE
new CipherInputStream(socket.getInputStream(), inCipher));
My key is genereated just fine, and the ObjectOutputStream is created ok, it just hangs at cipherIn.
The only odd part about the output is this, which is outputted twice before each of the inCipher.init's are executed:
java.io.IOException: Caching not supported for http://www.tgpr.org/LlamaChat/
at sun.plugin.cache.CachedJarLoader.download(CachedJarLoader.java:323)
at sun.plugin.cache.CachedJarLoader.load(CachedJarLoader.java:131)
at sun.plugin.cache.JarCache.get(JarCache.java:177)
at sun.plugin.net.protocol.jar.CachedJarURLConnection.connect(CachedJarURLConnection.java:71)
at sun.plugin.net.protocol.jar.CachedJarURLConnection.getJarFile(CachedJarURLConnection.java:56)
at javax.crypto.SunJCE_e.run(DashoA6275)
at java.security.AccessController.doPrivileged(Native Method)
at javax.crypto.SunJCE_d.a(DashoA6275)
at javax.crypto.SunJCE_d.a(DashoA6275)
at javax.crypto.SunJCE_d.verify(DashoA6275)
at javax.crypto.SunJCE_g.a(DashoA6275)
at javax.crypto.SunJCE_b.a(DashoA6275)
at javax.crypto.SunJCE_b.a(DashoA6275)
at javax.crypto.Cipher.getInstance(DashoA6275)
at ServerConnection.initializeCipher(ServerConnection.java:76)
at SD_Key.performAction(SD_Key.java:14)
at ServerConnection.<init>(ServerConnection.java:54)
at LlamaChat.connect(LlamaChat.java:195)
at LlamaChat.init(LlamaChat.java:78)
at sun.applet.AppletPanel.run(AppletPanel.java:341)
at java.lang.Thread.run(Thread.java:536)
can anyone help? I think i've tried everyting I can think of and i sure its possible to do this.
If you need more info to help, I'd be happy to provide :)
Thanks@
-Joe
Ok ... I was able to hack up the code a bit to break up getting the new ObjectInutStream, and it was able to execute the new CipherInputStream, but still hung on the new ObjectInputStream.
I took this a bit further and was able to transfer data over my Cipher(Input|Output)Stream.
I also tried different combinations of ordering the input and output and also tried comintations of Buffered(Input|Output)Streams on my other streams, but nothign worked :(
So ... I'm still in need of assistance.
Thanks!
- Joe
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RMI+JCE How to prevent the CipherInputStream hanging
Dear sir/Madam,
In our Rmi application, i bind the Server object with the JCE encryption,by implementing RMIClientSocketFactory,RMIServerSocketFactory.
ie i bind like this
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ie
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In the Class "EncSocket" i've overriden InputStream and OutputStream methods.
* Returns a stream of type XorOutputStream.
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while running the Server the Input and OutputStreams are created but at the time rebind,
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the server is hanging or waiting in the InputStream.
Your earliest reply is greatly appreciated.Iam breaking my head on this for the past one week.Million thanks for you.All the best
Awaiting for ur reply
kathiravanpls see http://forum.java.sun.com/thread.jsp?forum=58&thread=309785 for one of the solutions.
Bill -
Hi
I am having problems implementing CipherStreams. While encrypting objects with the Cipher-Class works perfectly fine, wrapping CipherStreams around ObjectStreams, or ObjectStreams around CipherStreams wont work. While i first tried to use the following:
inputstream
cipherinputstream(inputstream)
objectinputstream(cipherinputstream)
i tried to switch the cipher- and objectinputstream initialization, which in the end didnt change anything. What happens is:
Both ways compile ( NetBeans 3.5 ), but in both cases the program stops executing when trying to wrap a cipherstream around an inputstream or an objectinputstream ( same goes for outputstreams of course ).
No exception is being thrown, the program just stops.
Any suggestions? :)Ah, thx for your answer. While in my working code, i first created the OutputStream, and then the InputStream, i switched the order when implementing the CipherStreams. I am going to test it now, i guess though, that was the problem.
thx again, if this doesnt solve the problem, be sure to read again from me ;)
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Hi,
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this is the part of the server-code where the problem begins:
public int EscucharSocket(){
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Any help or idea?Hi again, thnx for your help
I modified my LE class so I just create a couple of Input/Output Streams per client (on server n client program), this is now the complete code of the class:
import java.net.*;
import java.io.*;
public class LE {
DataOutputStream dos;
ObjectOutputStream oos;
DataInputStream dis;
ObjectInputStream ois;
//Streams are created just once in the constructor
public LE (Socket s) throws Exception {
dos = new DataOutputStream(s.getOutputStream());
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dos.flush();
oos = new ObjectOutputStream (s.getOutputStream());
oos.flush();
dis = new DataInputStream(s.getInputStream());
ois = new ObjectInputStream (s.getInputStream());
public void EscribirByte(byte datos[],int len) throws Exception {
dos.write(datos,0,len);
dos.flush();
public void EscribirString(String dato) throws Exception {
dos.writeUTF(dato);
dos.flush();
public void EscribirChar(char dato) throws Exception {
dos.writeChar(dato);
dos.flush();
public void EscribirInt(int dato) throws Exception {
dos.writeInt(dato);
dos.flush();
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dos.writeLong(dato);
dos.flush();
public void EscribirObject(Object dato) throws Exception {
oos.writeObject(dato);
oos.flush();
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return dis.readInt();
public char LeerChar() throws Exception {
return dis.readChar();
public long LeerLong() throws Exception {
return dis.readLong();
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return ois.readObject();
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Server:
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cliente.close();
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catch(Exception e) {
return -1;
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I'm on the verge of lunacy because of this program.
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The moment you create an object input stream it tries to read a stream header from the underlaying stream. This means that both the server and the client stay wait for the other one to do something eternally. The fix is to make either the client or the server (but not both) create the output stream first. -
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import java.math.*;
import java.io.*;
import java.util.*;
import java.util.zip.*;
import java.security.*;
import java.security.spec.*;
import javax.crypto.*;
import javax.crypto.spec.*;
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catch(IOException io){
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catch(NoSuchAlgorithmException nsa){
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}That was what I wanted to do at first, but the
problem is that CipherOutputStream only has
write(byte[] b) method, not a writeObjetc method.. So
I cannot put the ObjectOutputStream inside a
CipherOutputStream. It doesn't work the other way
around either, the ObjectOutputStream cannot take a
CipherOutputStream as input.. as far as I could tell..ObjectOutputStream takes an OutputStream in it's constructor. A CipherOutputStream is an OutputStream since it is derived from it. -
I have a simple client/server app, and the client hangs when I try to get the input stream coming out of the server. I have the following code on the server:
ObjectOutputStream oos = null;
ObjectInputStream ois = null;
port = 49152;
server = new ServerSocket(port, 0, InetAddress.getLocalHost());
sock = server.accept();
oos = new ObjectOutputStream(sock.getOutputStream());
ois = new ObjectInputStream(sock.getInputStream());
String inMsg = (String) ois.readObject();
oos.writeObject(outMsg);
oos.close();
ois.close();
sock.close();And I try to invoke it with this code on the client:
ObjectOutputStream oos = null;
ObjectInputStream ois = null;
String inMsg = "";
int port = 49152;
try {
Socket sock = new Socket(InetAddress.getLocalHost(), port);
oos = new ObjectOutputStream(sock.getOutputStream());
ois = new ObjectInputStream(sock.getInputStream());//the code hangs here
oos.writeObject(outMsg);
inMsg = (String) ois.readObject();
oos.close();
ois.close();
sock.close();
} catch (Exception e) {
return "";
return inMsg;
The code hangs where indicated in the comments. Can someone tell me what I'm doing wrong?
Edited by: MidnightJava on Apr 10, 2008 4:55 AMCan you please explain the rationale for your suggestion? What sort of problem is it addressingThe constructor for ObjectOutputStream writes a header to the stream. The constructor for ObjectInputStream reads it. Try constructing them in the opposite order at both ends and you will see a lovely deadlock. The flush() is required if there is a BufferedOutputStream under the ObjectOutputStream.
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hi,
Using the following code I am sending a query to a server socket using a PrintWriter.println function and retrieve a vector object (results).
Client Code
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Second time on the Client-Side I get strange errors like "ClassCastException Java.lang.Object" and if I comment out the "while" line I get a "socket closed" error...
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I tried starting the ObjectInputStream inside the connect method (which initialized the connection with the ServerSocket object) but wheneven connect() was called the GUI hanged!
I don't know what am I doing wrong...
public void connect() throws Exception
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System.out.println("opening connection...to "+host+" at port "+port);
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output = socket.getOutputStream();
in = new DataInputStream(input);
out = new DataOutputStream(output);
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System.out.println("Connection established!");
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try{
if (socket != null)
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System.out.println("ERROR WHILE CONNECTING... SOCKET IS NOW CLOSED!");
}catch(IOException x){
x.printStackTrace();
else
throw new ClientException("connection active!");
} -
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I have been working on this little snippet of code all day and I cannot understand why I get null values when I run a display application. The code is posted below for 3 file. PhoneList.java is for serialization. CreatePhoneList is to populate a saved file with phone numbers and names of contacts. DisplaySavedPhoneList.java is to display the saved names and numbers. I'm not looking for the correct code, put for someone to point me in the right direction on why I'm getting these results so I can find a solution.
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public static void main(String[] args) throws IOException
ObjectOutputStream output = new ObjectOutputStream(new FileOutputStream("PhoneList.txt"));
PhoneList list;
String phName;
String phNum;
final String QUIT = "QUIT";
Scanner in = new Scanner(System.in);
System.out.println("Enter a phone number or " + QUIT + " to quit.");
phNum = in.next();
while(!phNum.equals(QUIT))
System.out.println("Enter the contact name.");
phName = in.next();
list = new PhoneList(phNum, phName);
output.writeObject(list);
System.out.println("Enter a phone number or " + QUIT + " to quit.");
phNum = in.next();
output.close();
}and this is the DisplaySavedPhoneList class:
import java.io.*;
import java.util.*;
public class DisplaySavedPhoneList
public static void main(String[] args) throws IOException, ClassNotFoundException
ObjectInputStream input = new ObjectInputStream(new FileInputStream("PhoneList.txt"));
PhoneList list;
final int SHOW = 1;
int showList;
int count = 0;
Scanner in = new Scanner(System.in);
try
System.out.print("To display Phone List enter " + SHOW);
showList = in.nextInt();
while(showList == SHOW)
list = (PhoneList)input.readObject();
System.out.println("Name: " + list.getName() + " Phone Number: " + list.getNum());
count++;
catch(EOFException e)
System.out.println("Oops, something broke!");
input.close();
}This is the result from running the DisplaySavedPhoneList application:
To display Phone List enter 1
1
Name: null Phone Number: null
Name: null Phone Number: null
Oops, something broke!ok, I did that, and its pointing me to the line commented below. I did a practical exercise where the code was almost identical and it worked fine. The only difference are the variables.
try
System.out.print("To display Phone List enter " + SHOW);
showList = in.nextInt();
while(showList == SHOW)
list = (PhoneList)input.readObject(); //this is the line that was identified in the stacktrace
System.out.println("Name: " + list.getName() + " Phone Number: " + list.getNum());
count++;
catch(EOFException e)
System.out.println("Stack Trace");
e.printStackTrace();
input.close();
}here is the total stack trace, in case you were wondering...
To display Phone List enter 1
1
Name: null Phone Number: null
java.io.EOFException
Name: null Phone Number: null
Stack Trace
at java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:2554)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1297)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351)
at DisplaySavedPhoneList.main(DisplaySavedPhoneList.java:21)I'm still not quite sure what this is telling me though. -
My Excel with PowerPivots acts weird, it hangs when i try to change font color
Hi
I am facing a weird issue using PowerPivot in my workbook, there is a worksheet named Charts in my workbook and all the charts i am using resides in that worksheet. Whenever i try to change the font color in that sheet, my excel's color palette goes blur
and then everything just freezes and turns black. This problem is happening only with Charts worksheet, when i try to change the color in other sheets, it works just, the problem is only with Charts sheet. File
size is 16 MB, there are just 10 pivot tables with some calculations and some calculated fields. There are no add-ins other than PowerPivot.
Thanks,
ShankerHi,
In regarding of the issue, please provide us more information to assist you better.
Do you receive any error message?
Which Excel version are you using? Excel 2013 or other?
Which workbook format are you using? XLS or XLSX?
Are you performing any specific task?
According to your description, this issue seems only occur with the special worksheet "Charts".
Firstly, I recommend we copy all of the content to a new/blank Excel file to test.
If it works fine, this issue might be caused by the "Charts" workbook itself. We'd better check the "Charts" workbook. Or re-build the file with a new workbook.
If it still makes Excel hang with a new file, this issue might due to the content. Please check the content first.
Secondly, we could follow below KB to troubleshoot this issue:
https://support2.microsoft.com/kb/2758592/en-us?wa=wsignin1.0
Thirdly, if the issue still exists, we may try to collect the Event log and App crash dump file to do advanced troubleshooting.
Event log:
http://windows.microsoft.com/en-US/windows7/Open-Event-Viewer
App crash dump file:
First enable app crash dump collection by copying following words into notepad, saving it as dump.reg and importing
it:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Windows Error Reporting\localdumps\EXCEL.EXE]
"DumpFolder"=hex(2):63,00,3a,00,5c,00,63,00,72,00,61,00,73,00,68,00,64,00,75,\
00,6d,00,70,00,73,00,00,00
"DumpCount"=dword:00000010
"DumpType"=dword:00000001
"CustomDumpFlags"=dword:00000000
Then, open Excel
to repro the issue. If crash issue appeared, please find the crashdump file under c:\.
To further help you, please upload this file into Skydrive and shared the link here.
Also, you can try to analyze dump by yourself if you would like to：
How to analyze app crash dump file:
http://blogs.technet.com/b/askperf/archive/2007/05/29/basic-debugging-of-an-application-crash.aspx
Hope it's helpful.
Regards,
George Zhao
TechNet Community Support
It's recommended to download and install
Configuration Analyzer Tool (OffCAT), which is developed by Microsoft Support teams. Once the tool is installed, you can run it at any time to scan for hundreds of known issues in Office
programs. -
Here's the detail of what happens.
1. Turn on computer and then click on Firefox icon on desktop.
2. Firefox opens. Everything looks OK. Mr Bunsen's graphic is working fine.
3. Click on any webpage link. For example, a newspaper or an online webmail page. All looks OK until
4. Click on anything or type anything, such as in ID in a box, and bingo, the top line of Firefox goes from dark blue to very pale blue and the computer is hung. You cannot get out of Firefox or get Firefox to work.
5. Switch off computer.
Is this perhaps due to a clash of Add-ons. I run Avast anti-virus. McAfee came with Firefox 4 and I did not reject it. Is it conflicting wth something in my system and causing it to hang?You can modify the pref <b>keyword.URL</b> on the <b>about:config</b> page to use Google's "I'm Feeling Lucky" or Google's "Browse By Name".
* Google "I'm Feeling Lucky": http://www.google.com/search?btnI=I%27m+Feeling+Lucky&ie=UTF-8&oe=UTF-8&q=
* Google "Browse by Name": http://www.google.com/search?ie=UTF-8&sourceid=navclient&gfns=1&q=
* http://kb.mozillazine.org/keyword.URL
* http://kb.mozillazine.org/Location_Bar_search -
putting a search option in the search box to the right of the address bar opens up the full search window but then Firefox hangs.
Your UserAgent string in Firefox is messed up by another program that you installed, and those websites don't know you are running Firefox 3.6.3 (which is what you do have installed).
[http://en.wikipedia.org/wiki/User_Agent]
type '''about:config''' in the URL bar and hit Enter
''If you see the warning, you can confirm that you want to access that page.''
Filter = '''general.useragent.'''
Right-click the preferences that are '''bold''', one line at a time, and select '''''Reset''''',
Then restart Firefox
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