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Java: ServerSocket reading data from a client

I am working on a simple programm for a university course. Here is the code that I have problems with:
//everything before this is unrelevant
String message = "";
BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
while((message = br.readLine()) != null) {
System.out.println(message);
}
//everything after this is irrelevant
I also have a thread for accepting incoming connections and some other stuff that is irrelevant. The problem that I have is that I can read one message and after that nothing happens. I guess the readLine() method is the problem but I am not really sure how to solve it.
It even says in our assignment to use
BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
to receive data.

Your client is only sending one line. You therefore don't need the loop. You should read one line and then do whatever you're supposed to do with it.

Client's BufferedReader not recieving line from Server, using sockets (Java)

I'm trying to make a chat application between a server and clients which are seperate classes. I'm not copying the whole code, but this is the part I'm not sure is set up correctly:
Server:
ServerSocket s = null;
Socket c = null;
s = new ServerSocket(5002);
c = s.accept();
BufferedReader in = new BufferedReader(new InputStreamReader(c.getInputStream()))
BufferedWriter out = new BufferedWriter(new OutputStreamWriter(c.getOutputStream()));
out.flush();
String line;
line = in.readLine();
out.write("#W|Welcome");
line = in.readLine();
out.write("#W|Welcome");
line = in.readLine();
out.write("#W|Welcome");
Client :
Socket socket = new Socket("localhost", 5002);
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream ()));
BufferedWriter out = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
String line;
out.flush();
out.write("#J|test");
line = in.readLine();
out.write("#J|test");
line = in.readLine();
After the client does out.println(), the server's in.readLine() gets the line. But when it's the other way around, the client keeps waiting at in.readLine(). (I used the debugger and watched the server execute out.println() and go past it, while the client is still stuck at in.readLine().
Are my data streams set up correctly or is there probably an error in my code somewhere else? I'm not sure how to check in the debugger if the streams are connected correctly.

[Quoting my comment above:]
There is nothing here that [reads or] writes lines.
That remains true. All you have is:
out.write("#W|Welcome");
etc.
don't forget to call newLine() as necessary
You forgot.

Cannot read line break/carriage return from socket response

I am sending setup commands to a TP-LINK wireless router through a telnet connection:
Trying 1.2.3.4...
Connected to 1.2.3.4.
Escape character is '^]'.
*HELLO*$$$
CMD
factory RESET
factory RESET
Set Factory Defaults
<4.00> set sys autoconn 0
set sys autoconn 0
AOK
<4.00>
...
I have a PHP code that performs the sending of commands and gets the response using sockets:
socket_write($socket, "factory RESET\r"); // send command
$response = socket_read($socket, 256); // get response
PHP works fine. The $response variable contains:
factory RESET
Set Factory Defaults
But using the Java I have problems. Using a BufferedReader object to read response, I can get the first line content. but I can not get the following lines:
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
// ...
bw.write("factory RESET");
bw.newLine();
bw.flush();
// ...
StringBuilder sb = new StringBuilder();
String s;
while ((s = br.readLine()) != null) {
sb.append(s);
}
I can get the first line content, but the second reading don't proceed and don't raise exception...
If I use the read function, only the first row is returned:
char[] buffer = new char[256];
br.read(buffer, 0, 256);
String response = new String(buffer); // response is "factory RESET"
What is the problem?

Your PHP code execute two reads. Your Java code attempts to read until end of stream, which only happens when the peer closes the connection. Do a single read.
The line separator in the Telnet protocol is defined as \r\n, unless you're using binary mode, which you aren't. Not as\r or whatever BufferedWriter may do on your platform.

Java TCP socket blocks at readLine

I'm working on a TCP client/server application and face the issue that the client is always blocking at br.readLine(). I tried to add a \n, but it did not solve the problem. Also a char array is blocking, when I only use read instead of readLine.
Client:
BufferedReader brInput = new BufferedReader(new InputStreamReader(System.in));
String send = brInput.readLine();
Socket socket = new Socket(host, port);
BufferedReader brSend = new BufferedReader(new InputStreamReader(socket.getInputStream()));
PrintWriter pr = new PrintWriter(socket.getOutputStream());
pr.println(send);
pr.flush();
System.out.println(brSend.readLine()); // is blocking
socket.close();
Server:
ServerSocket serverSocket = new ServerSocket(port);
while (true) {
Socket socket = serverSocket.accept(); // blocks until request is received
BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
String line;
while ((line = br.readLine()) != null) {
System.out.println(line);
if (line.isEmpty()) break;
}
PrintWriter pw = new PrintWriter(socket.getOutputStream());
pw.write("Hello world\n");
pw.flush();
pw.close();
socket.close();
}

Your code as written does this:
The client writes one line, and then tries to read one.
The server reads multiple lines until it either gets an empty line, or the end-of-stream. Then it writes a line.
The problem is that server is waiting for the client to do something that it isn't going to do:
the client won't send an empty line (unless it read one from standard input),
the client won't close the stream ... until it gets the response from the server.
Hence the client is waiting for the server and the server is waiting for the client. Deadlock.
There are various ways to solve this. One simple way would be to change this (in the client)
println(send);
to this
println(send); println();
However, the one problem here is that your "protocol" does not cope with the case wants to send an empty line as data. That is because you are implicitly using an empty line (from the client) to mean "message completed".

Read data from a Java Socket

I have a Socket listening on some x port.
I can send the data to the socket from my client app but unable to get any response from the server socket.
BufferedReader bis = new BufferedReader(new
InputStreamReader(clientSocket.getInputStream()));
String inputLine;
while ((inputLine = bis.readLine()) != null)
{
instr.append(inputLine);
}
This code part reads data from server.
But I can't read anything from server until unless the Socket on the server is closed.
Server code is not under my control to edit something on it.
How can I overcome this from client code.
Thanks

Looks like the server may not be sending newline characters (which is what the readLine() is looking for). Try something that does not rely on that. Here's an example that uses the buffer approach:
Socket clientSocket = new Socket("www.google.com", 80);
InputStream is = clientSocket.getInputStream();
PrintWriter pw = new PrintWriter(clientSocket.getOutputStream());
pw.println("GET / HTTP/1.0");
pw.println();
pw.flush();
byte[] buffer = new byte[1024];
int read;
while((read = is.read(buffer)) != -1) {
String output = new String(buffer, 0, read);
System.out.print(output);
System.out.flush();
};
clientSocket.close();

To communicate between a client and a server, a protocol needs to be well defined.
The client code blocks until a line is received from the server, or the socket is closed. You said that you only receive something once the socket is closed. So it probably means that the server doesn't send lines of text ended by an EOL character. The readLine() method thus blocks until such a character is found in the stream, or the socket is closed. Don't use readLine() if the server doesn't send lines. Use the method appropriate for the defined protocol (which we don't know).

For me this code is strange:
bis.readLine()
As I remember, this will try to read into a buffer until he founds a '\n'. But what if is never sent?
My ugly version breaks any design pattern and other recommendations, but always works:
int bytesExpected = clientSocket.available(); //it is waiting here
int[] buffer = new int[bytesExpected];
int readCount = clientSocket.read(buffer);
You should add the verifications for error and interruptions handling too.
With webservices results this is what worked for me ( 2-10MB was the max result, what I have sent)

Here is my implementation
clientSocket = new Socket(config.serverAddress, config.portNumber);
BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
while (clientSocket.isConnected()) {
data = in.readLine();
if (data != null) {
logger.debug("data: {}", data);
}
}