Java网络编程中不可以使用缓存吗？？

我使用缓存总是什么都不显示，但是又不抛出异常，也没有什么错！

http://blog.sina.com.cn/s/blog_616e189f0100s3px.html

是不是其他问题啊？可以使用缓存的，可以贴出主要代码

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class Fuwuqi {
public static void main(String[] args) {
try {
ServerSocket ss = new ServerSocket(8888);
System.out.println("服务器已经启动，正在等待连接。。。");
Socket s = ss.accept();

        InputStream in = s.getInputStream();
        BufferedReader br = new BufferedReader(new InputStreamReader(in));
        StringBuffer sb = new StringBuffer();
        char[] c = new char[2];
        int len = -1;
        while((len = br.read(c)) != -1){
            sb.append(c, 0, len);
        }System.out.println("fff");
        System.out.println(sb);

        OutputStream out = s.getOutputStream();
        BufferedOutputStream bos = new BufferedOutputStream(out);
        PrintWriter print = new PrintWriter(bos);
        print.println("嘿嘿");
        print.println("嘻嘻");
        bos.flush();

        print.close();
        out.close();
        br.close();
        in.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

}

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;

public class Kehuduan {
public static void main(String[] args) {
Socket s;
try {
s = new Socket("127.0.0.1", 8888);

        OutputStream out = s.getOutputStream();
        BufferedOutputStream bos = new BufferedOutputStream(out);
        PrintStream pw = new PrintStream(bos);
        pw.println("嘿嘿收到了吗？");
        pw.println("收到了回复！");
        bos.flush();

        InputStream in = s.getInputStream();
        BufferedReader br = new BufferedReader(new InputStreamReader(in));
        StringBuffer sb = new StringBuffer();
        char[] c = new char[2];
        int len = -1;
        while((len = br.read(c)) != -1){
            sb.append(c, 0, len);
        }
        System.out.println(sb);

        br.close();
        in.close();
        pw.close();
        out.close();
    } catch (UnknownHostException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

}

}