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CorruptedFrame exception , websockets in Netty

I was just playing around the websocket example client and server on netty wiki.
I modified the way server sends data to client.
Suddenly i started getting exception like "io.netty.handler.codec.CorruptedFrameException: bytes are not UTF-8"
This is on client and i am creating frame on server like this :-
ByteBuf buf = Unpooled.buffer();
buf.writeShort(1);
channel.write(new TextWebSocketFrame(buf))
I understand from error that bytebuf must be UTF-8 encoded , even the constructor of TextWebSocketFrame says this.
But i have no clue on why i am getting this error.
Any suggestions ?

You are getting this as you try to send non UTF-8 data. If you want to just send any binary data use a BinaryWebSocketFrame.

Sending Multiple Commands to device Through SSH

I am attempting to send multiple commands to a device using the SSHJ library. There is the option of sending multiple commands in this format:
Command command = sshSession.exec("show line; show ip interface brief;");
This works, but it is not always usable in my case. I have found other suggestions such as the second answer here.
When I attempt this suggestion the first command works fine and then it cycles between this error:
net.schmizz.sshj.connection.ConnectionException: Broken transport; encountered EOF
...
Caused by: net.schmizz.sshj.transport.TransportException: Broken transport; encountered EOF
or
Exception in thread "main" java.lang.IllegalStateException: Not connected
at net.schmizz.sshj.SSHClient.checkConnected(SSHClient.java:713)
at net.schmizz.sshj.SSHClient.startSession(SSHClient.java:651)
The code used is:
sshSession = sshClient.startSession();
Command command = sshSession.exec("sho ip int brie");
System.out.println(IOUtils.readFully(command.getInputStream()));//Just to see the reply while testing
command.join(5, TimeUnit.SECONDS);
sshSession = sshClient.startSession();
Command command2 = sshSession.exec("sho line");
System.out.println(IOUtils.readFully(command2.getInputStream()));//Just to see the reply while testing
A note if needed, the device I am connecting to, and majority of devices that it will connect to are Cisco networking equipment.
Thank you for any assistance.
-Jarrod

Never found a resolution for the exact problem. But I worked around the issue by using the DefaultPTY and providing my own streams with all the data I wanted to send. Playing around with this example.

Java app cannot communicate with RN-171 wifi module

I'm writing a Java code which have to send some data to an elecronic system and to receive some data from it through wireless. The electronic system is made of PIC32 and RN-171 module. I'm now trying to connect to the RN-171 network and to send and receive some data. Although I can in my java code set up an OutputStream and send some data to the RN-171 properly, I can't set up an InputStream and my app launches the following exception:
java.io.StreamCorruptedException: invalid stream header: 2A48454C
at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:804)
at java.io.ObjectInputStream.<init>(ObjectInputStream.java:299)
at TestController.sendParametersToWirelessModule(TestController.java:44)
at TestController.main(TestController.java:30)
The code in my java app, which generates the exception is:
try{
//1. creating a socket to connect to the server
requestSocket = new Socket("1.2.3.4", 2000);
System.out.println("Connected to localhost in port 2004");
//2. get Input and Output streams
out = new ObjectOutputStream(requestSocket.getOutputStream());
out.flush();
--> in = new ObjectInputStream(requestSocket.getInputStream());
//3: Communicating with the server
sendMessage(message); }
(The arrow indicates the code line which generates exception)
Is there a solution? Could anyone help me please?
Thanks

Use the following code instead:
out = requestSocket.getOutputStream();
in = requestSocket.getInputStream();
ObjectOutputStream/ObjectInputStream are used to serialize/deserialize Java objects. There is also no point in flushing the output stream before writing to it.

QSslSocket problem

I am trying to create a client - server application, the client written in c++ and QT, and the server in java, but I am having a really hard time trying to get ssl encryption working.
The process fails at handshake level, I think. The reason why I am having such a difficult time trying to figure out why it is not working is because, even though the process fails, no errors are reported in either the client or the server. I use the fallowing an the client side, in QT :
this->_uCertificate.fromPath(_DC::DEFAULT_CERT_MAIN_PATH + _DC::DEFAULT_MAIN_CERT_FILE);
this->_socket->addCaCertificate(this->_uCertificate);
//begin connection
this->_socket->connectToHostEncrypted(this->_uServerAdress, this->_uServerPort);
//wait until connection has completed
if(!this->_socket->waitForConnected(_CM::TIMEOUT))
{
this->_lastError = this->_socket->errorString();
return false;
}
//wait for handshake
if ( !this->_socket->waitForEncrypted(_CM::TIMEOUT) ) {
this->_lastError = this->_socket->errorString(); //the error is "No Error"
//return false;
}
It fails when calling the "waitForEncrypted". The function return false, so the process failed, but the error string is "No Error". I have also added a slot for handling the error signal from the socket, but it is never called. On the server side I use :
SSLSocket _sock = (SSLSocket) this._ssocket.accept();
_sock.startHandshake();
........................................
if(this._inputBuffered.read(this._messageBuffer) < 0)
throw new Exception("Error while reading from client");
Again no exceptions are thrown, but it fails at the read command. But on the server side I am no sure if an exception is thrown if the connection / handshake fails, or I should check for the error manually somehow.
I used to have a problem , in the client, when I would receive an error that the common name doesn't match the host, so at least I know that the connection is somewhat working. After I fixed the certificate to include the right common name, I am receiving this none existing error. Does anyone have an idea why it would fail this way, or at least a better debugging method?
Edit I have tried to connect using openSSL and it works. The handshake succeeds, and I can send and receive packets from the server. So the problem seems to be in the client.

It seemed that I had a problem with the way I was loading certificates from file. The method "fromPath" apparently doesn't actually load a cert from file, but returnes a list of certificates. If I add this list to my socket, then it works as it should. I am a bit conscience-stricken that I didn't read the documentation properly.
Edit The reason why it was failing, but still no errors were thrown with signals is because my socket had no valid certificate. When I was calling this->_uCertificate.fromPath(..), the method was returning a list of certificates found at that path, but the object itself was not modified. It still remained a invalid, empty certificate. So when I added that empty certificate in my socket, the only one, when it reached the handshake, It had no valid certificate for the operation. At this point it fails, but no errors are thrown.
But when the objects returned by the .fromPath() methon are added to the socket, then the handshake continues as normal, because now it has valid and non empty cartificates.

The problem of failing to give an error when there's an empty certificate database is now Qt bug QTBUG-17550

Connect your SSL client socket's void QSslSocket::sslErrors ( const QList<QSslError> & errors ) signal to some slot and see if there are any SSL errors reported.

Communication between java server and matlab client

I'd like to establish a server(Java)/client (Matlab) communication using socket. They can send messages to each other. An example shows how to do this in Java server and Java client, http://java.sun.com/docs/books/tutorial/networking/sockets/clientServer.html.
When I try to rewrite the client part in Matlab, I only can get the first message that the Java server sends and display it in the Matlab command window.
When I type a message in the Matlab command window, I can't pass it to the Java Server.
Jave code:
kkSocket = new Socket("localhost", 3434);
Matlab equivalent:
kkSocket = Socket('localhost', 3434);
Java code for client:
out = new PrintWriter(kkSocket.getOutputStream(), true);
in = new BufferedReader(new InputStreamReader(kkSocket.getInputStream()));
What would be a Matlab equivalent for this? Thanks in advance.

For the input stream:
input_stream = input_socket.getInputStream;
d_input_stream = DataInputStream(input_stream);
For the output stream:
output_stream = output_socket.getOutputStream;
d_output_stream = DataOutputStream(output_stream);

If you are trying to use MATLAB and the Java application on the same machine then matlabcontrol may do everything that you are looking for. It automatically establishes a connection to a session of MATLAB. It uses Java's Remote Method Invocation under the hood which makes use of sockets. matlabcontrol is designed specifically to only enable communication on localhost; the sockets it creates will not accept remote connections due to the security issues that could allow. However, if you need to allow remote connections you may find parts of matlabcontrol's source code to be useful.