Ошибка сокета C / C ++ в Java

Я пытаюсь установить сокет-связь между сервером Java и клиентом C. Когда я отправляю текст с клиента на сервер, например «AAAAA», я получаю сообщение об ошибке ниже. Почему это не работает? Я могу запустить эти коды с C на C и сценариями с Java на Java.

Waiting for connection
Connection received from 127.0.0.1
java.io.StreamCorruptedException: invalid stream header: 41414141
at java.io.ObjectInputStream.readStreamHeader(Unknown Source)
at java.io.ObjectInputStream.<init>(Unknown Source)
at Provider.run(Provider.java:22)
at Provider.main(Provider.java:67)
Exception in thread "main" java.lang.NullPointerException
at Provider.run(Provider.java:43)
at Provider.main(Provider.java:67)

Java сервер:

import java.io.*;
import java.net.*;
public class Provider{
ServerSocket providerSocket;
Socket connection = null;
ObjectOutputStream out;
ObjectInputStream in;
String message;
Provider(){}
void run()
{
try{
//1. creating a server socket
providerSocket = new ServerSocket(2004, 10);
//2. Wait for connection
System.out.println("Waiting for connection");
connection = providerSocket.accept();
System.out.println("Connection received from " + connection.getInetAddress().getHostName());
//3. get Input and Output streams
out = new ObjectOutputStream(connection.getOutputStream());
out.flush();
in = new ObjectInputStream(connection.getInputStream());
sendMessage("Connection successful");
//4. The two parts communicate via the input and output streams
do{
try{
message = (String)in.readObject();
System.out.println("client>" + message);
if (message.equals("bye"))
sendMessage("bye");
}
catch(ClassNotFoundException classnot){
System.err.println("Data received in unknown format");
}
}while(!message.equals("bye"));
}
catch(IOException ioException){
ioException.printStackTrace();
}
finally{
//4: Closing connection
try{
in.close();
out.close();
providerSocket.close();
}
catch(IOException ioException){
ioException.printStackTrace();
}
}
}
void sendMessage(String msg)
{
try{
out.writeObject(msg);
out.flush();
System.out.println("server>" + msg);
}
catch(IOException ioException){
ioException.printStackTrace();
}
}
public static void main(String args[])
{
Providerserver = new Provider();
while(true){
server.run();
}
}
}

Клиент C ++:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <conio.h>
#include <winsock2.h>

#define PORTNO      2004

void ExitSys();

int main(void)
{
WSADATA wsd;
int result;
SOCKET clientSocket;
struct sockaddr_in sinServer;
struct hostent *host;
char serverHost[] = "localhost";

if ((result = WSAStartup(MAKEWORD(2, 2), &wsd)) != 0)
ExitSys();

if ((clientSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) == INVALID_SOCKET)
ExitSys();

sinServer.sin_family = AF_INET;
sinServer.sin_port = htons(PORTNO);
sinServer.sin_addr.s_addr = inet_addr(serverHost);
if (sinServer.sin_addr.s_addr == INADDR_NONE) {
host = gethostbyname(serverHost);
if (host == NULL)
ExitSys();
memcpy(&sinServer.sin_addr.s_addr, host->h_addr_list[0], host->h_length);
}

if (connect(clientSocket, (struct sockaddr *) &sinServer, sizeof(sinServer)) == SOCKET_ERROR)
ExitSys();

printf("connected...\n");

for (;;) {
char buf[512];
printf("Text:");
gets(buf);
if (!strcmp(buf, "quit"))
break;
if (send(clientSocket, buf, strlen(buf), 0) == SOCKET_ERROR)
ExitSys();
}

shutdown(clientSocket, SD_BOTH);
closesocket(clientSocket);

WSACleanup();

return 0;
}

void ExitSys()
{
printf("extited");
}