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java InputStream doesn't return -1 at end [duplicate]

I am supposed to develop a simple SFTP.
Things were going fine until my ByteArrayOutputStream (in this case, baos) was not writing all of the arrayByte. Can some please explain to me, why the system hangs on me?
Server Side:
public static void main (String[] args)
{
int portTexto = 5656;
String comando;
String regexGet = "\\s*(get)\\s[A-z0-9]*\\.[A-z0-9]*\\s*";
String regexPut = "\\s*(put)\\s[A-z0-9]*\\.[A-z0-9]*\\s*";
try{
ServerSocket servSockTexto = new ServerSocket(portTexto);
// pegar IP de servidor.
try {
InetAddress addr = InetAddress.getLocalHost();
System.out.println(addr.getHostAddress());
}
catch (UnknownHostException e) {
}
System.out.println("Aguardando conexão com Servidor de Texto...");
Socket sock = servSockTexto.accept();
System.out.println("Conexão com Servidor estabelecida.");
//BufferedOutputStream paraCliente = new BufferedOutputStream(sock.getOutputStream());
DataInputStream inputServ = new DataInputStream(sock.getInputStream());
DataOutputStream outputServ = new DataOutputStream(sock.getOutputStream());
BufferedOutputStream paraCliente = new BufferedOutputStream(sock.getOutputStream());
//1
outputServ.writeUTF("Conexão com Servidor estabelecida.");
do
{
//3
comando = inputServ.readUTF();
if(comando.matches(regexGet))
{
String[] aux = comando.split("\\s");
String nomeArq = aux[1];
File arqGet = new File(nomeArq);
//4
outputServ.writeUTF(arqGet.getName());
byte[] arrayByte = new byte[(int) arqGet.length()];
FileInputStream fInput = new FileInputStream(arqGet);
BufferedInputStream bInput = new BufferedInputStream(fInput);
bInput.read(arrayByte, 0, arrayByte.length);
//5
paraCliente.write(arrayByte.length);
//6
paraCliente.write(arrayByte, 0, arrayByte.length);
paraCliente.flush();
bInput.close();
fInput.close();
}
else if(comando.matches(regexPut))
{
}
else if (!comando.equals("sair"))
{
//4
outputServ.writeUTF("Comando não existente.");
}
}
while(!comando.equals("sair"));
servSockTexto.close();
sock.close();
inputServ.close();
outputServ.close();
paraCliente.close();
}
catch (Exception ex)
{
System.out.println("Erro: " + ex);
}
}
Client Side:
public static void main (String[] args)
{
String IP = "localhost";
String comando;
String regexGet = "\\s*(get)\\s[A-z0-9]*\\.[A-z0-9]*\\s*";
String regexPut = "\\s*(put)\\s[A-z0-9]*\\.[A-z0-9]*\\s*";
int portTexto = 5656;
Scanner scan = new Scanner(System.in);
try{
Socket sock = new Socket (IP,portTexto);
//BufferedInputStream is = new BufferedInputStream(sock.getInputStream());
DataInputStream inputCli = new DataInputStream(sock.getInputStream());
DataOutputStream outputCli = new DataOutputStream(sock.getOutputStream());
InputStream is = sock.getInputStream();
//BufferedInputStream is = new BufferedInputStream(sock.getInputStream());
//1
System.out.println(inputCli.readUTF());
do
{
System.out.println("Digite um comando:");
comando = scan.nextLine();
//3
outputCli.writeUTF(comando);
if(comando.matches(regexGet))
{
//4
String arqTeste = "C:\\Users\\Frederico\\Desktop\\Download SFTP\\" + inputCli.readUTF();
int bytesRead;
ByteArrayOutputStream baos = new ByteArrayOutputStream(); FileOutputStream fos = new FileOutputStream( arqTeste );
BufferedOutputStream bos = new BufferedOutputStream(fos);
//5
byte[] aByte = new byte[1];
//6
bytesRead = is.read(aByte, 0, aByte.length);
// MY SYSTEM STAYS INSIDE THIS DO AND I CANT SOLVE THIS!!!
do
{
baos.write(aByte);
bytesRead = is.read(aByte);
}
while (bytesRead != -1);
//is.close();
bos.write(baos.toByteArray());
bos.flush();
bos.close();
}
else if(comando.matches(regexPut))
{}
else if (!comando.equals("sair"))
{
//4
System.out.println(inputCli.readUTF());
}
}
while(!comando.equals("sair"));
is.close();
sock.close();
inputCli.close();
outputCli.close();
System.out.println("Conexão com servidor encerrada.");
}
catch (Exception ex)
{
System.out.println("Erro: " + ex);
}
}

Your do/while loop runs until end of stream but the peer is never closing the socket. The protocol seems to require keeping the socket open for further commands, so you will have to adjust this part of it to include a length-word prefix so you know how many bytes to copy.
The question isn't about ByteArrayOutputStream not writing all your bytes, it is about blocking in is.read().

File transfer (.png , .txt) between Server and Client using UDP

I wrote a server and client for client to connect to the server and select a data from the server's directory to transfer the data with UDP protocol but the problem is, it is only working for .txt files it isn't working for .png files and also in the .txt files the output files are not the same with the original one forexample lines between words are not there and all the words printed side by side instead of line by line. How can i fix this problem ?
Server side:
import java.io.*;
import java.net.*;
public class FTPServer {
public static void main(String[] args)
{
DatagramSocket socket = null;
DatagramPacket inPacket = null;
DatagramPacket outPacket = null;
byte[] inBuf, outBuf;
String msg;
final int PORT = 50000;
try
{
socket = new DatagramSocket(PORT);
while(true)
{
System.out.println("\nRunning...\n");
inBuf = new byte[1000];
inPacket = new DatagramPacket(inBuf, inBuf.length);
socket.receive(inPacket);
int source_port=inPacket.getPort();
InetAddress source_address = inPacket.getAddress();
msg = new String(inPacket.getData(), 0, inPacket.getLength());
System.out.println("CLient: " + source_address + ":" + source_port);
String dirname = "/home/erke/Desktop/data";
File f1 = new File(dirname);
File fl[] = f1.listFiles();
StringBuilder sb = new StringBuilder("\n");
int c=0;
for(int i = 0;i<fl.length;i++)
{
if(fl[i].canRead())
c++;
}
sb.append(c+ " files found.\n\n");
for(int i=0; i<fl.length;i++)
sb.append(fl[i].getName()+ " " + fl[i].length()+ " Bytes\n");
sb.append("\nEnter file name to Download: ");
outBuf = (sb.toString()).getBytes();
outPacket = new DatagramPacket(outBuf, 0, outBuf.length, source_address, source_port);
socket.send(outPacket);
inBuf = new byte[1000];
inPacket = new DatagramPacket(inBuf, inBuf.length);
socket.receive(inPacket);
String filename = new String(inPacket.getData(), 0, inPacket.getLength());
System.out.println("Requested File: " + filename);
boolean flis = false;
int index =-1;
sb = new StringBuilder("");
for(int i=0;i<fl.length;i++)
{
if(((fl[i].getName()).toString()).equalsIgnoreCase(filename))
{
index = i;
flis = true;
}
}
if(!flis)
{
System.out.println("ERROR");
sb.append("ERROR");
outBuf = (sb.toString()).getBytes();
outPacket = new DatagramPacket(outBuf, 0, outBuf.length, source_address, source_port);
socket.send(outPacket);
}
else
{
try
{
//File send
File ff=new File(fl[index].getAbsolutePath());
FileReader fr = new FileReader(ff);
BufferedReader brf = new BufferedReader(fr);
String s = null;
sb=new StringBuilder();
while((s=brf.readLine())!=null)
{
sb.append(s);
}
if(brf.readLine()==null)
System.out.println("File Read Succesfull, CLosing Socket");
outBuf=new byte[100000];
outBuf = (sb.toString()).getBytes();
outPacket = new DatagramPacket(outBuf, 0, outBuf.length,source_address, source_port);
socket.send(outPacket);
} catch (Exception ioe) {
System.out.println(ioe);
}
}
}
} catch (Exception e){
System.out.println("Error\n");
}
}
}
Client side:
import java.io.*;
import java.net.*;
import java.util.Scanner;
public class FTPClient {
public static void main(String[] args) {
DatagramSocket socket = null;
DatagramPacket inPacket = null;
DatagramPacket outPacket = null;
byte[] inBuf, outBuf;
final int PORT = 50000;
String msg = null;
Scanner src = new Scanner(System.in);
try
{
InetAddress address = InetAddress.getByName("127.0.0.1");
socket = new DatagramSocket();
msg = "";
outBuf =msg.getBytes();
outPacket = new DatagramPacket(outBuf, 0, outBuf.length,address,PORT);
socket.send(outPacket);
inBuf = new byte[65535];
inPacket = new DatagramPacket(inBuf, inBuf.length);
socket.receive(inPacket);
String data = new String(inPacket.getData(), 0, inPacket.getLength());
//Print file list
System.out.println(data);
//Send file name
String filename = src.nextLine();
outBuf = filename.getBytes();
outPacket = new DatagramPacket(outBuf, 0, outBuf.length, address, PORT);
socket.send(outPacket);
//Receive file
inBuf = new byte[100000];
inPacket = new DatagramPacket(inBuf, inBuf.length);
socket.receive(inPacket);
data = new String(inPacket.getData(), 0, inPacket.getLength());
if(data.endsWith("ERROR"))
{
System.out.println("File doesn't exists.\n");
socket.close();
}
else
{
try
{
BufferedWriter pw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(filename)));
pw.write(data);
//Force write buffer to Fİle
pw.close();
System.out.println("File Write Succesful. Closing Socket");
socket.close();
} catch (Exception ioe) {
System.out.println("File Error\n");
socket.close();
}
}
} catch (Exception e) {
System.out.println("\nNetwork Error. Try Again Later. \n");
}
}
}

In your code you are using String to store file data in both client and the server. In order to be able to transfer any file other then a text file, in your server you should have a byte[] buffer instead of String, and use it for loading file contents. You can do this by using classes with names ending with InputStream. After you do that send those bytes over a network. Same goes for the client.
InputStream and OutputStream are used to read\write bytes from files directly, while Reader and Writer classes are specifically intended to work with text files. You cannot read\write bytes with these classes, they work only with characters and strings. You will still be able to transfer text files too though since they are also just an array of bytes.
Also you should be using TCP if you want to transfer your files without losing packets, which UDP tends to do as it doesn't have mechanisms to ensure that packets are safely delivered to a destination like TCP does.

Why Is my code only sending part of a Large File

Im trying to make a Java Socket File Server but I have hit a dead end, It seems to be working until in around loop 4080 then seems to stop, Any ideas as to why this is happening? here is my code:
public class FileSender extends Thread{
private final int PORT = 7777;
private Socket sock;
private DataInputStream fileStream;
private OutputStream out;
private File file ;
public void run() {
try {
file = new File("path");
if(file.exists()){
System.out.println("Found File");
if(file.canRead()){
System.out.println("Can Read File");
}
}
this.fileStream = new DataInputStream(new FileInputStream(file));
sock = new Socket("localhost",PORT);
out = sock.getOutputStream();
copyStream(fileStream, out, file);
} catch (IOException ex) {
Logger.getLogger(FileSender.class.getName()).log(Level.SEVERE, null, ex);
}
}
public void copyStream(DataInputStream in, OutputStream out, File file) throws IOException{
byte[] buf = new byte[1024];
int total = 0;
while(file.getTotalSpace() != total){
int r = in.read(buf);
if(r != -1){
out.write(buf, 0, r);
}
total += r;
}
out.flush();
System.out.println("Total was:" + total);
}
}
This is My Server:
public class FileReceiver extends Thread {
private final int PORT = 7777;
private ServerSocket sSoc;
private DataInputStream in;
public void run() {
try {
byte[] buf = new byte[1024];
sSoc = new ServerSocket(PORT);
Socket conn = sSoc.accept();
in = new DataInputStream(new BufferedInputStream(conn.getInputStream()));
File file = new File("C:\\test.rar");
if (!file.exists()) {
file.createNewFile();
}
if (file.canWrite()) {
FileOutputStream fos = new FileOutputStream(file);
int x= 0 ;
do {
in.read(buf);
System.out.println(x + " : " + buf);
fos.write(buf);
x++;
} while (in.read(buf) != -1);
System.out.println("Complete");
}
} catch (IOException ex) {
Logger.getLogger(FileReceiver.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
EDIT : The program will send a small text file but onlky sends part of a Larger File.

Your condition in the while loop in copyStream seems wrong. Please try and change it to the following and try.
public void copyStream(DataInputStream in, OutputStream out, File file) throws IOException{
byte[] buf = new byte[1024];
int total = 0;
while(true){
int r = in.read(buf);
if(r != -1){
out.write(buf, 0, r);
total += r;
} else {
break;
}
}

The problem was in my server I was calling in.read() twice forcing anything larger then a single buffer size to miss segments.

Java sending and receiving file (byte[]) over sockets

I am trying to develop a very simple client / server where the client converts a file to bytes, sends it to the server, and then converts the bytes back in to a file.
Currently the program just creates an empty file. I'm not a fantastic Java developer so any help much appreciated.
This is the server part that receives what the client sends.
ServerSocket serverSocket = null;
serverSocket = new ServerSocket(4444);
Socket socket = null;
socket = serverSocket.accept();
DataOutputStream out = new DataOutputStream(new BufferedOutputStream(socket.getOutputStream()));
DataInputStream in = new DataInputStream(new BufferedInputStream(socket.getInputStream()));
byte[] bytes = new byte[1024];
in.read(bytes);
System.out.println(bytes);
FileOutputStream fos = new FileOutputStream("C:\\test2.xml");
fos.write(bytes);
And here is the client part
Socket socket = null;
DataOutputStream out = null;
DataInputStream in = null;
String host = "127.0.0.1";
socket = new Socket(host, 4444);
out = new DataOutputStream(new BufferedOutputStream(socket.getOutputStream()));
in = new DataInputStream(new BufferedInputStream(socket.getInputStream()));
File file = new File("C:\\test.xml");
//InputStream is = new FileInputStream(file);
// Get the size of the file
long length = file.length();
if (length > Integer.MAX_VALUE) {
System.out.println("File is too large.");
}
byte[] bytes = new byte[(int) length];
//out.write(bytes);
System.out.println(bytes);
out.close();
in.close();
socket.close();

The correct way to copy a stream in Java is as follows:
int count;
byte[] buffer = new byte[8192]; // or 4096, or more
while ((count = in.read(buffer)) > 0)
{
out.write(buffer, 0, count);
}
Wish I had a dollar for every time I've posted that in a forum.

Thanks for the help. I've managed to get it working now so thought I would post so that the others can use to help them.
Server:
public class Server {
public static void main(String[] args) throws IOException {
ServerSocket serverSocket = null;
try {
serverSocket = new ServerSocket(4444);
} catch (IOException ex) {
System.out.println("Can't setup server on this port number. ");
}
Socket socket = null;
InputStream in = null;
OutputStream out = null;
try {
socket = serverSocket.accept();
} catch (IOException ex) {
System.out.println("Can't accept client connection. ");
}
try {
in = socket.getInputStream();
} catch (IOException ex) {
System.out.println("Can't get socket input stream. ");
}
try {
out = new FileOutputStream("M:\\test2.xml");
} catch (FileNotFoundException ex) {
System.out.println("File not found. ");
}
byte[] bytes = new byte[16*1024];
int count;
while ((count = in.read(bytes)) > 0) {
out.write(bytes, 0, count);
}
out.close();
in.close();
socket.close();
serverSocket.close();
}
}
and the Client:
public class Client {
public static void main(String[] args) throws IOException {
Socket socket = null;
String host = "127.0.0.1";
socket = new Socket(host, 4444);
File file = new File("M:\\test.xml");
// Get the size of the file
long length = file.length();
byte[] bytes = new byte[16 * 1024];
InputStream in = new FileInputStream(file);
OutputStream out = socket.getOutputStream();
int count;
while ((count = in.read(bytes)) > 0) {
out.write(bytes, 0, count);
}
out.close();
in.close();
socket.close();
}
}

Here is the server
Open a stream to the file and send it overnetwork
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
public class SimpleFileServer {
public final static int SOCKET_PORT = 5501;
public final static String FILE_TO_SEND = "file.txt";
public static void main (String [] args ) throws IOException {
FileInputStream fis = null;
BufferedInputStream bis = null;
OutputStream os = null;
ServerSocket servsock = null;
Socket sock = null;
try {
servsock = new ServerSocket(SOCKET_PORT);
while (true) {
System.out.println("Waiting...");
try {
sock = servsock.accept();
System.out.println("Accepted connection : " + sock);
// send file
File myFile = new File (FILE_TO_SEND);
byte [] mybytearray = new byte [(int)myFile.length()];
fis = new FileInputStream(myFile);
bis = new BufferedInputStream(fis);
bis.read(mybytearray,0,mybytearray.length);
os = sock.getOutputStream();
System.out.println("Sending " + FILE_TO_SEND + "(" + mybytearray.length + " bytes)");
os.write(mybytearray,0,mybytearray.length);
os.flush();
System.out.println("Done.");
} catch (IOException ex) {
System.out.println(ex.getMessage()+": An Inbound Connection Was Not Resolved");
}
}finally {
if (bis != null) bis.close();
if (os != null) os.close();
if (sock!=null) sock.close();
}
}
}
finally {
if (servsock != null)
servsock.close();
}
}
}
Here is the client
Recive the file being sent overnetwork
import java.io.BufferedOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.Socket;
public class SimpleFileClient {
public final static int SOCKET_PORT = 5501;
public final static String SERVER = "127.0.0.1";
public final static String
FILE_TO_RECEIVED = "file-rec.txt";
public final static int FILE_SIZE = Integer.MAX_VALUE;
public static void main (String [] args ) throws IOException {
int bytesRead;
int current = 0;
FileOutputStream fos = null;
BufferedOutputStream bos = null;
Socket sock = null;
try {
sock = new Socket(SERVER, SOCKET_PORT);
System.out.println("Connecting...");
// receive file
byte [] mybytearray = new byte [FILE_SIZE];
InputStream is = sock.getInputStream();
fos = new FileOutputStream(FILE_TO_RECEIVED);
bos = new BufferedOutputStream(fos);
bytesRead = is.read(mybytearray,0,mybytearray.length);
current = bytesRead;
do {
bytesRead =
is.read(mybytearray, current, (mybytearray.length-current));
if(bytesRead >= 0) current += bytesRead;
} while(bytesRead > -1);
bos.write(mybytearray, 0 , current);
bos.flush();
System.out.println("File " + FILE_TO_RECEIVED
+ " downloaded (" + current + " bytes read)");
}
finally {
if (fos != null) fos.close();
if (bos != null) bos.close();
if (sock != null) sock.close();
}
}
}

To avoid the limitation of the file size , which can cause the Exception java.lang.OutOfMemoryError to be thrown when creating an array of the file size byte[] bytes = new byte[(int) length];, instead we could do
byte[] bytearray = new byte[1024*16];
FileInputStream fis = null;
try {
fis = new FileInputStream(file);
OutputStream output= socket.getOututStream();
BufferedInputStream bis = new BufferedInputStream(fis);
int readLength = -1;
while ((readLength = bis.read(bytearray)) > 0) {
output.write(bytearray, 0, readLength);
}
bis.close();
output.close();
}
catch(Exception ex ){
ex.printStackTrace();
} //Excuse the poor exception handling...

Rookie, if you want to write a file to server by socket, how about using fileoutputstream instead of dataoutputstream? dataoutputstream is more fit for protocol-level read-write. it is not very reasonable for your code in bytes reading and writing. loop to read and write is necessary in java io. and also, you use a buffer way. flush is necessary. here is a code sample: http://www.rgagnon.com/javadetails/java-0542.html

Adding up on EJP's answer; use this for more fluidity.
Make sure you don't put his code inside a bigger try catch with more code between the .read and the catch block, it may return an exception and jump all the way to the outer catch block, safest bet is to place EJPS's while loop inside a try catch, and then continue the code after it, like:
int count;
byte[] bytes = new byte[4096];
try {
while ((count = is.read(bytes)) > 0) {
System.out.println(count);
bos.write(bytes, 0, count);
}
} catch ( Exception e )
{
//It will land here....
}
// Then continue from here
EDIT: ^This happened to me cuz I didn't realize you need to put socket.shutDownOutput() if it's a client-to-server stream!
Hope this post solves any of your issues

Missing bytes in sending files over TCP connection

Some bytes are missing when I'm sending files over TCP connection. Though there are times that file transfer is complete.
Sending side:
class SendFile extends Thread {
Socket s;
String toIP;
String fileName;
PrintWriter pw;
BufferedReader br;
String fromIP;
String nextHopIP;
String transferTime;
int routingIndex;
final int bufferSize = 65536;
int readFile;
byte[] buffer;
FileInputStream fileIn;
OutputStream fileOut;
long fileTransferTime;
SendFile(String toIP, String fileName) {
this.toIP = toIP;
this.fileName = fileName;
}
public void run() {
while (true) {
try {
fromIP = InetAddress.getLocalHost().getHostAddress();
nextHopIP = Tables.checkRoutingTable(toIP);
if (nextHopIP.equals("none")) {
System.out.println("Invalid IP address");
} else {
s = new Socket(nextHopIP, 3434);
fileIn = new FileInputStream(fileName);
fileOut = s.getOutputStream();
buffer = new byte[bufferSize];
pw = new PrintWriter(s.getOutputStream());
br = new BufferedReader(new InputStreamReader(s.getInputStream()));
pw.println(fromIP);
pw.println(toIP);
pw.println(fileName.split("\\\\")[fileName.split("\\\\").length - 1]);
pw.flush();
//Send file
fileTransferTime = System.currentTimeMillis();
int sum = 0;
while ((readFile = fileIn.read(buffer)) != -1) {
fileOut.write(buffer, 0, readFile);
sum += readFile;
}
System.out.println(sum);
fileIn.close();
s.shutdownOutput();
br.readLine();
fileTransferTime = System.currentTimeMillis() - fileTransferTime;
System.out.println("File transfer time: " + fileTransferTime + " ms");
s.close();
break;
}
} catch (IOException ex) {
//Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
System.out.println("Connection timed out. Retrying...");
}
}
}
}
Receiving side:
class FileTransferThread extends Thread {
Socket fromSocket;
Socket toSocket;
String ip;
BufferedReader fromBR;
BufferedReader toBR;
PrintWriter fromPW;
PrintWriter toPW;
String[][] delta;
String token;
String toIP;
String fromIP;
String nextHopIP;
String absoluteFileName;
String fileName;
int deltaCount;
int entryCount;
int socketIndex;
int i;
int j;
int readFile;
final int bufferSize = 65536;
byte[] buffer;
InputStream fileIn;
FileOutputStream fileOut;
OutputStream fileHopOut;
File directory;
long fileTransferTime;
FileTransferThread(Socket s) {
this.fromSocket = s;
}
public void run() {
try {
ip = InetAddress.getLocalHost().getHostAddress();
fromBR = new BufferedReader(new InputStreamReader(fromSocket.getInputStream()));
fromPW = new PrintWriter(fromSocket.getOutputStream());
fromIP = fromBR.readLine();
toIP = fromBR.readLine();
nextHopIP = Tables.checkRoutingTable(toIP);
buffer = new byte[bufferSize];
fileIn = fromSocket.getInputStream();
fileName = fromBR.readLine();
if (!fileName.equals("\\send")) {
directory = new File("c:\\" + fromIP);
directory.mkdirs();
absoluteFileName = "c:\\" + fromIP + "\\" + fileName;
fileOut = new FileOutputStream(absoluteFileName);
while (true) {
try {
//if not yet the destination IP, pass to next hop
if (!toIP.equals(ip)) {
toSocket = new Socket(toIP, 3434);
fileHopOut = toSocket.getOutputStream();
toBR = new BufferedReader(new InputStreamReader(toSocket.getInputStream()));
toPW = new PrintWriter(toSocket.getOutputStream());
toPW.println(fromIP);
toPW.println(toIP);
toPW.println(fileName);
toPW.flush();
//Send file
while ((readFile = fileIn.read(buffer)) != -1) {
fileHopOut.write(buffer, 0, readFile);
}
toSocket.shutdownOutput();
fromPW.println(toBR.readLine());
fromPW.flush();
toSocket.close();
} else {
int sum = 0;
while ((readFile = fileIn.read(buffer)) != -1) {
fileOut.write(buffer, 0, readFile);
sum += readFile;
}
System.out.println(sum);
fileOut.flush();
fileOut.close();
fromPW.println("1");
fromPW.flush();
}
fromSocket.close();
break;
} catch (IOException ex) {
//Logger.getLogger(FileTransferThread.class.getName()).log(Level.SEVERE, null, ex);
System.out.println("Connection timed out. Retrying...");
}
}
} else {
while(true) {
try {
//if not yet the destination IP, pass to next hop
if (!toIP.equals(ip)) {
toSocket = new Socket(toIP, 3434);
fileHopOut = toSocket.getOutputStream();
toBR = new BufferedReader(new InputStreamReader(toSocket.getInputStream()));
toPW = new PrintWriter(toSocket.getOutputStream());
toPW.println(fromIP);
toPW.println(toIP);
toPW.println(fileName);
toPW.flush();
//Send file
while ((readFile = fileIn.read(buffer)) != -1) {
fileHopOut.write(buffer, 0, readFile);
}
toSocket.shutdownOutput();
fromPW.println(toBR.readLine());
fromPW.flush();
toSocket.close();
} else {
while ((readFile = fileIn.read(buffer)) != -1) {
}
fromPW.println("1");
fromPW.flush();
}
fromSocket.close();
break;
}
catch (IOException ex) {
//Logger.getLogger(FileTransferThread.class.getName()).log(Level.SEVERE, null, ex);
System.out.println("Connection timed out. Retrying...");
}
}
}
fromSocket.close();
} catch (IOException ex) {
Logger.getLogger(FileTransferThread.class.getName()).log(Level.SEVERE, null, ex);
}
}
}

You are not closing - and hence not flushing - the SocketOutputStream called fileout. (You really should consider less misleading names ...).
Hm ... it appears shutdownOutput does that; its javadoc writes:
Disables the output stream for this socket.
For a TCP socket, any previously written data will be sent
followed by TCP's normal connection termination sequence.
If you write to a socket output stream after invoking
shutdownOutput() on the socket, the stream will throw
an IOException.
I leave this in case anybody else has the same idea.

Note that socket.getInputStream specifies the sorts of data loss that can happen using that facility. In particular:
The network software may discard bytes
that are buffered by the socket.

Found the error. It seems that BufferedReader is getting a chunk of data which is supposed to be for the file.