How to detect a -1 in while reading data from socket

Question

Hi
Am faced with a problem in socket reading
Whenever I try to read any data from a socket and I encounter a -1, I assume that the steam has reached End of File and close that connection. This logic was introduced overcome a problem of connection getting closed from the server and the client connection hanging in CLOSE_WAIT state.
Now the problem if the server sends a -1 as part of the data, how do I differenciate between -1 to indicate the End of stream and -1 in the actual data
thanks in advance
jcool

Answer 1

As dannyyates states, the possible return values for read() are a single byte (0..255) or an end of stream (-1), so you have 257 total possible values there. If the other side wrote a byte equal to -1 from its perspective, you would receive a 255 in Java (since both are represented 11111111 in binary - one is interpreted as signed and one is interpreted as unsigned). Your return value from read is between 0x00000000 and 0x000000FF (hex) since read() returns an int (32 bits) rather than a byte (8 bits) and EOF is returned as 0xFFFFFFFF.
Honestly, though, you might just consider using the read(byte[]) method where appropriate. It is much more efficient for reads of more than one byte at a time; it reads a bunch of bytes into an array. Its return value is how many bytes it read, with -1 indicating EOF.