Java(서버) 와 C(클라이언트) 간에 통신하는 소켓프로그래밍문제인데요..

C서버코딩
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <winsock2.h>
 
#define BUF_SIZE 1024
 
int main(int argc, char *argv[])
{
	WSADATA wsaData;
	SOCKET hServSock, hClntSock;
	char message[BUF_SIZE];
	char modifiedmessage[BUF_SIZE];
	int strLen, i;
 
	SOCKADDR_IN servAdr, clntAdr;
	int clntAdrSize;
 
	if(argc!=2) {
		printf("Usage : %s <port>\n", argv[0]);
		exit(1);
	}
 
	WSAStartup(MAKEWORD(2, 2), &wsaData);
 
	hServSock=socket(PF_INET, SOCK_STREAM, 0);   
 
	memset(&servAdr, 0, sizeof(servAdr));
	servAdr.sin_family=AF_INET;
	servAdr.sin_addr.s_addr=htonl(INADDR_ANY);
	servAdr.sin_port=htons(atoi(argv[1]));
 
	bind(hServSock, (SOCKADDR*)&servAdr, sizeof(servAdr));
 
	listen(hServSock, 5);
 
	clntAdrSize=sizeof(clntAdr);
 
	while(1)
	{
		hClntSock=accept(hServSock, (SOCKADDR*)&clntAdr, &clntAdrSize);
		while((strLen=recv(hClntSock, message, BUF_SIZE, 0))!=0)
		{
			for(i=0; message[i]!='\0'; i++)
				modifiedmessage[i] = toupper(message[i]);
			modifiedmessage[i] = '\0';
			send(hClntSock, modifiedmessage, strLen, 0);
		}
		closesocket(hClntSock);
	}
	closesocket(hServSock);
	WSACleanup();
	return 0;
}
 
java 클라이언트 코딩
 
import java.io.*;
import java.net.*;
 
class TCP_Client_Java {
	public static void main(String argv[]) throws Exception
	{
		String sentence;
		String modifiedSentence;
		System.out.print("Input Character : ");
		BufferedReader inFromUser = new BufferedReader(new InputStreamReader(System.in));
		Socket clientSocket = new Socket("127.0.0.1",1234);
		DataOutputStream outToServer = new DataOutputStream(clientSocket.getOutputStream());
		BufferedReader inFromServer = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
		sentence = inFromUser.readLine();
		outToServer.writeBytes(sentence +'\n');
		modifiedSentence = inFromServer.readLine();
		System.out.println("From Server : " + modifiedSentence);
		clientSocket.close();
	}
}