Better way to communicate between TCP Client and Server

I have a commandsystem to communicate between my TCP Server and Client (Java). I can send specific commands to my Client, if the Client received a command, it will execute something.

Basically, thats working. But sometimes I have to send the command + extra informations. The problem is: The informations will sometimes be sent too fast. So some information will get lost / mixed up and my Client cant execute the request properly. The solution for me was to use Thread.sleep(), but this isn't clean nor efficent. Because there is still a risk that the information will not be received properly.

My Server:

public void sendCommand(Socket socket) throws InterruptedException, IOException {
    writeMsg("CMD_POPUP", socket);
    Thread.sleep(150);
    writeMsg("foo", socket);
    Thread.sleep(150);
    writeMsg("bar", socket);
    Thread.sleep(150);
    writeMsg("baz", socket);
}

public void writeMsg(String message, Socket socket) throws IOException {
    DataOutputStream out = new DataOutputStream(socket.getOutputStream());
    out.writeUTF(message);
}

My Client:

public void interpreteCommand(Socket socket) throws IOException {
    while (true) {
        switch (readMsg(socket)) {
            case "CMD_POPUP":
                System.out.println(readMsg(socket)); 
                System.out.println(readMsg(socket)); //Sometimes it would be 'bar' but also sometimes it would be 'baz'
                System.out.println(readMsg(socket)); //Sometimes it would be 'baz' but also sometimes it would be nothing
                break;
        }
    }
}

public String readMsg(Socket socket) throws IOException {
    DataInputStream in = new DataInputStream(new BufferedInputStream(socket.getInputStream()));
    return in.readUTF();
}