Java - WebSocket sending Hex 0x0A

I have been working on Android(Java) App, to create a websocket server,
all went good, and the connection is accepted.

The problem is sending a message to client (Browser webSocket)

    OutputStream writer = client.getOutputStream();
    // FIN OPCODE 1000 0001
    writer.write(0x81);

    // message length
    writer.write(0x5);

    writer.write('H');
    writer.write('e');
    writer.write('l');
    writer.write('l');
    writer.write('o');
    writer.flush();

I got an Error : failed: Invalid frame header

i installed webshark to see the problem:

On the Right you will see the data

- 0x0A -> the problem.

• 0x81 -> FIN & OPCODE (10000001)
• 0x05 -> length of the message
• 0x48 0x65 0x6c 0x6c -> Hell

====== MORE CODE =======

How i read the client request (headers) ?

private String readClientInputStream() {
    String str = null;
    try {
        InputStream in = client.getInputStream();
        byte[] buffer = new byte[1024];
        int countBytesRead = in.read(buffer);
        if (countBytesRead > 0) {
            str = new String(buffer, 0, countBytesRead);
        }
    } catch (IOException e) {
        e.printStackTrace();
    }

    return str;
}

Using str to get Sec-WebSocket-Key and sending response (handshake):

public void sendWebSocketHandShake(String str) {
    String[] result = str.split("Sec-WebSocket-Key: ", -1)[1].split("\\n");
    String key = makeKeyAccept(result[0]); // METHOD CODE BELLOW
    StringBuilder handshake_str = new StringBuilder();
    handshake_str.append("HTTP/1.1 101 Switching Protocols\n");
    handshake_str.append("Upgrade: websocket\n");
    handshake_str.append("Connection: Upgrade\n");
    handshake_str.append("Sec-WebSocket-Accept: ").append(key).append("\n");
    handshake_str.append("\n");
    try {
        OutputStream out = client.getOutputStream();
        byte[] b = handshake_str.toString().getBytes(StandardCharsets.UTF_8);
        out.write(b, 0, b.length);
        out.flush();

    } catch (IOException e) {
        e.printStackTrace();
    }

}

How i make Sec-WebSocket-Accept key ?

   public String makeKeyAccept(String key) {
        String _acceptKey = key.trim() + WEBSOCKET_KEY_MAGIC;
        MessageDigest digest = null;
        String base64 = null;
        try {
            digest = MessageDigest.getInstance("SHA-1");
            digest.update(_acceptKey.getBytes(StandardCharsets.UTF_8));
            byte[] encoded = android.util.Base64.encode(digest.digest(), 0, digest.getDigestLength(), android.util.Base64.DEFAULT);
            base64 = new String(encoded, 0, encoded.length, StandardCharsets.UTF_8);
        } catch (Exception ignore){}

        return base64;
    }

Thank you @MarkRotteveel

As he told me the problem could be from the handshake and left over byte..

i fixed it by using trim() after creating the key base64