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Android Client Socket IOException

EDIT: The problem is the input in the Client.class so when the Android devices receives an answer from the Server. Those are the following lines that causes the crash:
InputStream input = client.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(input));
String text;
while ((text = reader.readLine()) != null) {
Log.d("ClientLog", "Received from Server"+ text);
}
Here is my Client.class in Android:
public class Client implements Runnable{
public Client() {
}
#Override
public void run() {
try {
Log.d("ClientLog", "Socket creation incoming");
Socket client = new Socket("localhost", 5555);
Log.d("ClientLog", "Client has been started");
// Streams:
OutputStream out = client.getOutputStream();
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(client.getOutputStream()));
InputStream input = client.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(input));
// -----------------------------------------------------------------------
writer.write("Test");
writer.newLine();
writer.flush();
String text;
while ((text = reader.readLine()) != null) {
Log.d("ClientLog", "Received from Server"+ text);
}
writer.close();
reader.close();
} catch (UnknownHostException e) {
Log.d("ClientLog", "Error: Host not found");
e.printStackTrace();
} catch (IOException e) {
Log.d("ClientLog", "Error: IOException");
e.printStackTrace();
}
}
}
And if needed my Server.class in Java:
public class Server {
public static void main(String[] args) {
ExecutorService executor = Executors.newFixedThreadPool(30);
ServerSocket server;
try {
server = new ServerSocket(5555);
System.out.println("Server has been started on Port 5555");
while(true) {
try {
Socket client = server.accept();
//Thread t = new Thread(new Handler(client));
//t.start();
executor.execute(new Handler(client));
} catch (IOException e) {
System.out.println("Error IOExceotion");
e.printStackTrace();
}
}
} catch (IOException e1) {
e1.printStackTrace();
}
}
The Handler.class needed for Server.class:
public class Handler implements Runnable{
private Socket client;
public Handler(Socket pClient) {
client = pClient;
}
#Override
public void run() {
try {
// Streams:
OutputStream out = client.getOutputStream();
PrintWriter writer = new PrintWriter(out);
InputStream input = client.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(input));
// -----------------------------------------------------------------------
String text = null;
while ((text = reader.readLine()) != null) {
writer.write(text+ "\n");
writer.flush();
System.out.println("Recieved from Client: "+ text);
}
//Close Streams
writer.close();
reader.close();
client.close();
} catch (IOException e) {
System.out.println("Error IOException");
e.printStackTrace();
}
}
}

The debugging was resolved in the comments above.
Step 1: Add permissions to the android manifest file as was outlined here: Java socket IOException - permission denied
Step 2: Change the while ((text = reader.readLine()) != null) check. I guess the text = reader.readLine() != null check was problematic.

Forwarding all input to Java Process

I'm trying to forward the input to the process. It's a minecraft server so I need to send commands to it. I try in this way but it doesn't send anything. (I've also checked the log file)
public static void main(String[] args) throws IOException {
File file = new File("spigot.jar");
if(file.exists()) {
ProcessBuilder builder = new ProcessBuilder("java", "-jar", "spigot.jar");
Process p = builder.start();
new Thread(() -> {
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
String s = "";
try {
while((s = br.readLine()) != null) {
System.out.println(s);
}
} catch (IOException e) {
e.printStackTrace();
}
}).start();
new Thread(()-> {
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(p.getOutputStream()));
BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
String cmd = "";
try {
while((cmd = input.readLine()) != null) {
bw.write(cmd);
bw.flush();
}
} catch (IOException e) {
e.printStackTrace();
}
}).start();
new Thread(() -> {
while(true) {
if(!p.isAlive()) {
System.out.println("Server closed.");
System.exit(0);
}
}
}).start();
} else {
System.out.println("spigot.jar not found.");
System.exit(0);
}
}
EDIT:
I rewrote the code using threads but i'm getting the same problem

Solved.
I need to add "bw.newline()" to send ENTER, and make the server execute my command

Multithreading with client server program

I am trying to implement multi threading with a client/server program I have been working on. I need to allow multiple clients to connect to the server at the same time. I currently have 4 classes: a Client, a Server, a Protocol and a Worker to handle the threads. The following code is what I have for those classes:
SocketServer Class:
public class SocketServer {
public static void main(String[] args) throws IOException {
int portNumber = 9987;
try (
ServerSocket serverSocket = new ServerSocket(portNumber);
Socket clientSocket = serverSocket.accept();
PrintWriter out =
new PrintWriter(clientSocket.getOutputStream(), true);
BufferedReader in = new BufferedReader(
new InputStreamReader(clientSocket.getInputStream()));
) {
Thread thread = new Thread(new ClientWorker(clientSocket));
thread.start(); //start thread
String inputLine, outputLine;
// Initiate conversation with client
Protocol prot = new Protocol();
outputLine = prot.processInput(null);
out.println(outputLine);
while ((inputLine = in.readLine()) != null) {
outputLine = prot.processInput(inputLine);
out.println(outputLine);
if (outputLine.equals("quit"))
break;
}
} catch (IOException e) {
System.out.println("Exception caught when trying to listen on port "
+ portNumber + " or listening for a connection");
System.out.println(e.getMessage());
}
}
}
SocketClient Class:
public class SocketClient {
public static void main(String[] args) throws IOException
{
String hostName = "localhost";
int portNumber = 9987;
try (
Socket socket = new Socket(hostName, portNumber);
PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
BufferedReader in = new BufferedReader(
new InputStreamReader(socket.getInputStream()));
) {
BufferedReader stdIn =
new BufferedReader(new InputStreamReader(System.in));
String fromServer;
String fromUser;
while ((fromServer = in.readLine()) != null) {
System.out.println("Server: " + fromServer);
if (fromServer.equals("quit"))
break;
fromUser = stdIn.readLine();
if (fromUser != null) {
System.out.println("Client: " + fromUser);
out.println(fromUser);
}
}
} catch (UnknownHostException e) {
System.err.println("Don't know about host " + hostName);
System.exit(1);
} catch (IOException e) {
System.err.println("Couldn't get I/O for the connection to " +
hostName);
System.exit(1);
}
}
}
Protocol Class:
public class Protocol {
private static final int waiting = 0;
private static final int sentPrompt = 1;
private int status = waiting;
public String processInput(String theInput) {
String theOutput = null;
if (status == waiting) {
theOutput = "Please enter what you would like to retrieve: 'customer' or 'product' ";
status = sentPrompt;
}
else if ( status == sentPrompt ) {
if ( theInput.equalsIgnoreCase("product")) {
File f = new File("product.txt");
Scanner sc = null;
try {
sc = new Scanner(f);
} catch (FileNotFoundException ex) {
Logger.getLogger(Protocol.class.getName()).log(Level.SEVERE, null, ex);
}
while ( sc.hasNextLine() ) {
String line = sc.nextLine();
theOutput = "The current product entries are : " + line;
}
return theOutput;
}
else if ( theInput.equalsIgnoreCase("customer")) {
File f = new File("customer.txt");
Scanner sc = null;
try {
sc = new Scanner(f);
} catch (FileNotFoundException ex) {
Logger.getLogger(Protocol.class.getName()).log(Level.SEVERE, null, ex);
}
while ( sc.hasNextLine() ) {
String line = sc.nextLine();
theOutput = "The current customer entries are : " + line;
}
return theOutput;
}
else if ( theInput.equalsIgnoreCase("quit")) {
return "quit";
}
else {
return "quit";
}
}
return theOutput;
}
}
The ClientWorker Class:
public class ClientWorker implements Runnable {
private final Socket client;
public ClientWorker( Socket client ) {
this.client = client;
}
#Override
public void run() {
String line;
BufferedReader in = null;
PrintWriter out = null;
try {
System.out.println("Thread started with name:"+Thread.currentThread().getName());
in = new BufferedReader(new InputStreamReader(client.getInputStream()));
out = new PrintWriter(client.getOutputStream(), true);
} catch (IOException e) {
System.out.println("in or out failed");
System.exit(-1);
}
while (true) {
try {
System.out.println("Thread running with name:"+Thread.currentThread().getName());
line = in.readLine();
//Send data back to client
out.println(line);
//Append data to text area
} catch (IOException e) {
System.out.println("Read failed");
System.exit(-1);
}
}
}
}
When I run the server and client, everything works fine as expected. Then when I try to run another client, it just hangs there and does not prompt the client to give a response. Any insight into what I am missing is greatly appreciated!

Your server code should address implement below functionalities.
Keep accepting socket from ServerSocket in a while loop
Create new thread after accept() call by passing client socket i.e Socket
Do IO processing in client socket thread e.g ClientWorker in your case.
Have a look at this article
Your code should be
ServerSocket serverSocket = new ServerSocket(portNumber);
while(true){
try{
Socket clientSocket = serverSocket.accept();
Thread thread = new ClientWorker(clientSocket);
thread.start(); //start thread
}catch(Exception err){
err.printStackTrace();
}
}

How many times does serverSocket.accept() get called?
Once.
That's how many clients it will handle.
Subsequent clients trying to contact will not have anybody listening to receive them.
To handle more clients, you need to call serverSocket.accept() in a loop.

Java: Buffered Reader waiting for input before updating

I am programming a small ChatServer program, and I've nailed down the error to this part of the client code
public void run() {
Client client = new Client();
try {
Socket s = new Socket("localhost", 25555);
client.os = new DataOutputStream(s.getOutputStream());
InputStreamReader isr = new InputStreamReader(s.getInputStream());
BufferedReader br = new BufferedReader(isr);
while (!exit){
String str = Input.read_string();
client.os.writeUTF(ID+"=CLID"+str.toLowerCase());
client.os.flush();
System.out.println(br.readLine());
}
} catch ( IOException e) {
e.printStackTrace();
}
}
The Input.read_string() code is the following:
class Input{
public static String read_string() {
String read="";
try {
read = new BufferedReader(new InputStreamReader(System.in), 1).readLine();
} catch (IOException ex) {
System.out.println("error reading from the input stream!");
}
return read;
}
}
When I put the System.out.println(br.readLine()); at the beginning of the while loop the first time another client chats, but after that one has to input to get the next update.
Also, this may be fixed with the last error, but when it does update, it is the last thing the other client sent.

BufferedWriter.write() does not seem to work

I have two Java applications, where an Android client connects to a server on a computer and sends a message using BufferedWriter over websockets.
The client:
try {
toast("Sending...");
Socket sock = new Socket(ip, PORT);
OutputStream os = sock.getOutputStream();
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(os));
bw.flush();
bw.write("Hello Server!");
toast("Connected!");
} catch (UnknownHostException e) {
toast(e.getMessage());
} catch (IOException e) {
toast(e.getMessage());
}
The server:
public static void main(String[] args) {
ServerSocket server;
ConnectionThread ct;
Socket s;
ExecutorService es = Executors.newSingleThreadExecutor();
try {
System.out.println("Starting server...");
server = new ServerSocket(1337);
s = server.accept();
ct = new ConnectionThread(s);
es.execute(ct);
} catch (IOException ex) {
ex.printStackTrace();
}
}
The ConnectionThread class:
public class ConnectionThread implements Runnable {
private Socket sock;
private InputStream is;
private BufferedReader br;
private boolean online;
public ConnectionThread(Socket s) {
System.out.println("Creating connection thread.");
this.sock = s;
online = true;
}
#Override
public void run() {
String input = "";
try {
System.out.println("Starting to read...");
is = sock.getInputStream();
br = new BufferedReader(new InputStreamReader(is));
while (online) {
input = br.readLine();
if(input != null){
System.out.print("Received message: ");
System.out.println(input);
}
}
br.close();
is.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
When I run the server, and then the client, the client will show the "Connected!" toast, and the server's output will be:
Starting server...
Creating connection thread.
Starting to read...
So, it seems like the connection is actually being made, but the message does not arrive. Does anybody know why this could be happening?

Your server is expecting a complete line terminated by a newline. Try:
bw.write("Hello Server!");
bw.newLine();

Do it like this...
String s = new String();
while ((br.readLine())!=null) {
s = s+br.readLine();
System.out.print("Received message: ");
System.out.println(input);
}
}
And
bw.println("Hello Server");

I notice that you don't send an endline on your client, so the BufferedReader.readline() will never return, because it cannot match the \n-character. Try it again with
bw.write("Hello Server!\n");
on the client side.