Streams without boundaries

A TCP socket is a byte stream with no message boundaries. Write three JSON objects to a socket and the reader may receive three chunks, one chunk, or one-and-a-half — the network owes you neither your send boundaries nor your read sizes. Everything message-shaped is YOUR protocol's job: framing.

Socket s = new Socket("localhost", port);        // loopback: safe, instant
s.setSoTimeout(500);                             // read() throws after 500ms idle
BufferedReader in = new BufferedReader(
    new InputStreamReader(s.getInputStream(), StandardCharsets.UTF_8));
in.readLine();                                   // frame = "until newline"

The newline protocol is the classic first frame: sender appends \n, reader splits on it. It is text-only and it forbids embedded newlines — binary protocols graduate to length prefixes ([4-byte length][payload]), which is what HTTP/2 and every serious wire format do. Either way, the framing rule belongs to the protocol, not the stream.

Timeouts are survival: a read against a silent peer blocks forever by default. setSoTimeout bounds every read; production servers also bound idle connections and total request time. A socket without a timeout is a thread-leak with a delay.