C# to Java Byte Conversion

I'm attempting to build a TCP Client in C# that passes over files (mainly MP3) over to an Android application, but I'm having great difficulty converting between unsigned and signed bytes.

What am I doing wrong to get the mismatch in values retrieved by the app?

The below is the data C# is sending across via TCP.

new byte[] { 9, 1, 251, 252, 253, 254, 255, 254, 253, 252, 251, }

Java

while ((charsRead = in.read(buffer)) != -1)
{
    serverMessage = new String(buffer).substring(0, charsRead);
    serverByteMessage = serverMessage.getBytes();
    for(int i = 0; i < serverByteMessage.length; i++) {
        int bi = serverByteMessage[i] & 0xFF;
        Log.e("TCP Client", "Item: " + serverByteMessage[i]);
        Log.e("TCP Client", "Value of my test unsigned byte: " + bi);
    }
}

Java Output

Item: 9
Value of my test unsigned byte: 9
Item: 1
Value of my test unsigned byte: 1
Item: -17
Value of my test unsigned byte: 239
Item: -65
Value of my test unsigned byte: 191
Item: -67
Value of my test unsigned byte: 189
Item: -17
Value of my test unsigned byte: 239
Item: -65
Value of my test unsigned byte: 191
Item: -67
Value of my test unsigned byte: 189
Item: -17
Value of my test unsigned byte: 239
Item: -65
Value of my test unsigned byte: 191
Item: -67
Value of my test unsigned byte: 189
Item: -17
Value of my test unsigned byte: 239
Item: -65
Value of my test unsigned byte: 191
Item: -67
Value of my test unsigned byte: 189
Item: -17
Value of my test unsigned byte: 239

Solution

When you convert binary to text, you can only convert valid byte encodings to text. If you convert random data to text, any invalid code are typically replaced with a ?

The simple solution is to avoid mixing text and binary unless you really know what you are doing.

InputStream in = socket.getInputStream();
int bytesRead;
byte[] bytes = new bytes[512];
while((bytesRead = in.read(bytes)) > 0) {
   for (int i =0; i < bytesread; i++) {
       int bi = bytesRead[i] & 0xFF;
       System.out.println(bi);
   }
}

Note: You cannot assume that TCP supports messages. It only supports a stream of bytes. Your have to have a protocol which allows you to work out when a message starts/finishes. e.g. you should send the length of the message before the actual message.