WebSocket server fails to properly handle hexadecimal data from clients

//java
//function
public byte[] hexStringToByteArray(String s) {
        int len = s.length();
        if (len % 2 != 0) {
            throw new IllegalArgumentException("Hex string must have an even length");
        }
        byte[] data = new byte[len / 2];
        for (int i = 0; i < len; i += 2) {
            data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
                    + Character.digit(s.charAt(i+1), 16));
        }
        return data;
    }

 @Override
    public void onMessage(WebSocket conn, ByteBuffer message) {
        //Log.d("websocket", "onMessage() Listen ByteBuffer data->"+ByteUtil.byteBufferToString(message));

        byte[] bytes = new byte[message.remaining()];
        message.get(bytes);

        Log.d("websocket", "onMessage() Listen ByteBuffer data->"+byteArrayToHexString(bytes));
        res.post(new Runnable() {
            @Override
            public void run() {
                res.setText("Byte Listen:"+byteArrayToHexString(bytes));
            }
        });
    }

//python socketClient
import asyncio
import websockets

async def send_byte_array():
    uri = "ws://192.168.0.102:9093"
    byte_data = bytes([0x02, 0x47, 0x00, 0xda, 0x5d, 0x4f, 0xf2, 0x02]) /// my byte

    async with websockets.connect(uri) as websocket:
        await websocket.send(byte_data)
        print("Sent byte data:", byte_data.hex())

async def receive_byte_array():
    uri = "ws://192.168.0.102:9093"  

    async with websockets.connect(uri) as websocket:
        while True:
            byte_data = await websocket.recv() 
            hex_string = byte_data.hex()
            print("Received byte data:", hex_string)

async def main():
    await asyncio.gather(send_byte_array(), receive_byte_array())

asyncio.get_event_loop().run_until_complete(main())