🚀 go-pugleaf

hello all
see my program following:

	public static void main(String args[]) {
		Socket socket = null;
		BufferedReader in = null;
		PrintWriter out = null;
		String line = null;

		try {
			socket = new Socket("myserver", 21);
			in = new BufferedReader(new InputStreamReader(socket
					.getInputStream()));
			out = new PrintWriter(socket.getOutputStream());
			out.println("user " + "congzb");
			out.println("pass " + "1qazxsw2");
			out.println("pwd");

			
			out.println("pasv");
			out.println("list");

			out.println("quit");
			out.flush();

			while ((line = in.readLine()) != null) {
				System.out.println(line);
			}

		} catch (Exception e) {
			System.out.println(e.getMessage());
		} finally {
			try {
				out.close();
				in.close();
				socket.close();
			} catch (Exception fe) {
				System.out.println("RESOURCE CLOSE EXCEPTION "
						+ fe.getMessage());
			}
		}
	}



the trace info as following:

331 Password required for congzb.
230-Last unsuccessful login: Fri Feb 17 02:21:26 EST 2006 on /dev/pts/1 from 9.186.23.101
230-Last login: Fri Feb 17 05:59:26 EST 2006 on ftp from ::ffff:9.186.23.101
230 User congzb logged in.
257 "/home/congzb" is current directory.
227 Entering Passive Mode (9,56,249,42,152,101)


in fact, it hang on "pasv" command. and don't give me the answer of "list" command.

why? thanks