Difference in read/write between Windows Vs Linux

Question

Hi,
Can you please write, whether it is a bug or my ignorance. I thought, if a java program runs in Windows then it will run in other platform too, without editing any code. It proved me wrong. So is it a bug?
Ref: Fedora linux version 5
Kernel ver. 2.6.17
jdk version - build 1.5.0_06-b05
I was working on a web service. The server side program connects to an application using socket program and sends back data to client.
While it was working very fine with Windows XP. When I moved the service to Linux (above said linux). The program stopped working. When I explored it, I found 3 things.
1. I was using PrintWriter
PrintWriter outputStream = new PrintWriter(new OutputStreamWriter(socket.getOutputStream()), true);
to write into the socket. It works fine in Windows but not in Linux. ie. it sends different bytes in linux. Thus fails. When I changed it to BufferedOutputStream it works fine.
BufferedOutputStream outputStream = new BufferedOutputStream (socket.getOutputStream());
2. I was using BufferedReader to read
BufferedReader inputStream = new BufferedReader(new InputStreamReader(socket.getInputStream()));
data from socket. It reads. But byte varies from expectation. The same program works very well with windows.
I used DataInputStream now. that works. but..
DataInputStream inputStream = new DataInputStream(socket.getInputStream());
3. While reading it was suppossed to read 2098 bytes, instead it reads 1448 bytes. It reads correctly in Windows, but not in the above said linux.
Is it a bug or there is a difference in reading and writing from socket between Windows and Linux ( even though it is same JVM).
Thanks
Sasi.

Answer 1

Thanks a lot for both of you.
I believe, \r\n Vs \n could not be the reason.
Because, I was sending binary data.Then you should not be using Writer at all!
>
With regard to "utf-8", I thought of that but I did
not try to issue it in the function. Because, I was
trying to send and receive raw binary data.Then you should not be using Writer at all!
>
Now, You may ask that why did you use PrintWriter.
Because, the data had unsigned byte values. Makes no difference - you should not be using Writer at all!
So I
converted everything in to char array and send it.Will cause you problems at some point on some platform unless you use Base64 or HEX encoding.
especially, whereever unsigned byte was required, I
used (byte & Oxff). It worked very well with
Windows. So I just go ahead doing other things.I use byte & 0xff for dealing with unsigned valued but your use sounds dangerous.
>
Here my question is, I assumed that if a program is
written in java and complied on jvm x, then
irrespective of the underlying OS, if the jvm is the
same x, then the program should run without error. Is
it wrong. If it is not wrong, then is it a jre bug?Your program will work if you have not used any implicit or explicit platform dependencies. For example, if in your program then you have hard codes a path as "C:\Program Files" then it will work on Windows (but then only if it has a C drive) but not on Unix.
Any program has to deal with a number of platform specific features and Java protects you from them as much as possible BUT you must deal with things like Locale, EOL and default character encoding.
No! Of course it is not a jre bug. You have coded to a specific platform and are then are suprised when it fails on other platforms.
>
Did you see my third point of my original problem
statement. How to solve that.Since I don't have a view of your code I can't make an informed comment. I think I can guess what the problem is but I won't speculate.