在一个自己建的类中用到了out.println(),怎么解释？

Question

这个类没有继承任何其他类，除了Object,但是Object中并没有成员out呀，哪里来的这句呢out.println(" ... ");整个类为：
import java.net.*;
import java.io.*;public class Client
{    public static void main(String[] args) throws Exception
    {
        InetAddress addr = InetAddress.getByName(null);
        System.out.println("address=" + addr);
        Socket socket = new Socket(addr, Demo2.PORT);
        try
        {
            System.out.println("socket=" + socket);
            BufferedReader in = new BufferedReader(new InputStreamReader(socket
                    .getInputStream()));
            PrintWriter out = new PrintWriter(new BufferedWriter(
                    new OutputStreamWriter(socket.getOutputStream())),true);
            for (int i = 0; i < 10; i++)
            {
                out.println("howdy"+i);/////////？？？？？
                String str=in.readLine();
                System.out.println(str);
            }
            out.println("end");///////////？？？？？？？        }
        finally
        {
            System.out.println("closing");
            socket.close();        }
    }
}

Answer 1

那是你自己定义的局部变量 PrintWriter out