Hi Jim ,

Thanks for your posting. From your description, you're using the dotnet's
XmlSerializer to serialize a certain class instance out to a NetWorkStream
and at the other side, when you retrieve the stream and try reading the
xmlcontent out, you found there is an additional header "o;?" at the
begining of the xml stream ,yes?

As for the problem you mentioned, I think it is likely due to the encoding
problem. First, as for UNICODE text stream, there will has a header which
indicate the Unicode stream's encoding type. And "o;?" is the one for
UTF-8, and when using other ones such as UTF-16, you will get other value(
ASCII stream won't have such a header).  To verify this, you can also use a
UltraEdit to open a unicode(UTF-8) txt file and use hex format to see it,
you'll found the header,  it is composed of three bytes  239,187,191 ,
they're all ascii char, and will display as "o;?" if you print them as
ascii string. For example:

byte[] bytes = {239,187,191};  
MessageBox.Show(System.Text.Encoding.ASCII.GetString(bytes));

So, when you use XmlSerializer to serialize an object into a certain
stream, if using Unicode encoding type(use UTF-8 for instance), the header
will be added( the first three bytes). However, if you read the xml back
from the stream via  UTF-8 encoding, you won't get this three bytes, the
UTF-8 encoding system will automatically remove the header and return the
sequential bytes bebind the header. Here is a simple code snippet to show
this:

===============================
byte[] buffer = null;

XmlSerializer serializer = new XmlSerializer(typeof(userInfo));
           
userInfo ui = new userInfo();
ui.userName = "steven cheng";
ui.age = 20;
ui.email = "steven@microsoft.com";

MemoryStream ms = new MemoryStream();

StreamWriter sw = new StreamWriter(ms,System.Text.Encoding.UTF8);

serializer.Serialize(sw,ui);

buffer = ms.GetBuffer();
           
// will return the xml with "o;?"  because we use ASCII to decode the byte
which is incorrect
MessageBox.Show(System.Text.Encoding.ASCII.GetString(buffer));
           
// won't display the "o;?" since the UIF-8(correct encoding) will bypass it
MessageBox.Show(System.Text.Encoding.UTF8.GetString(buffer));
==================================

So, If you found the problems occur in your java client that recieve this
stream, I suggest you check the java code to see whether it is reading the
stream and conver the bytes to string using the correct encoding
type(utf-8). I suspect that it is using the default  ASCII encoding to read
the bytes so that the "o;?" come out.

Please have a look at the above things, if there is anything unclear,
please feel free to post here.
HTH.

Regards,

Steven Cheng
Microsoft Online Support

My .Net socket test client WAS erroneously using Encoding.ASCII (ah, the
joys of midnight testing!), changing that to UTF8 produces the same result
that the Java developer is reporting -  a "?" is received at the beginning
of every deserialized message on the socket.

So, the "o;" is the encoding information on the packet, but the "?" is
extraneous.

What is the source of the extraneous character, and can it/should it be
eliminated? I seem to recall something like this from the days of DOS - is
it just an artifact of Socket communications in general?

a

it

read

My .Net socket test client WAS erroneously using Encoding.ASCII (ah, the
joys of midnight testing!), changing that to UTF8 produces the same result
that the Java developer is reporting -  a "?" is received at the beginning
of every deserialized message on the socket.

So, the "o;" is the encoding information on the packet, but the "?" is
extraneous.

What is the source of the extraneous character, and can it/should it be
eliminated? I seem to recall something like this from the days of DOS - is
it just an artifact of Socket communications in general?

a

it

read