Question

I’m developing an application for Android 4.03. The code of relevance is this:

public void startConnection() {
    new Thread(new Runnable() {
        @Override
        public void run() {
            try {
                Log.i(LOG_TAG, "Beginning");

                _socket = new Socket(_server, _port);
                _socket.setSoTimeout(DEFAULT_SOCKET_TIMEOUT);

                _writer = new BufferedWriter(new OutputStreamWriter(_socket.getOutputStream()));
                _reader = new BufferedReader(new InputStreamReader(_socket.getInputStream()));

                _in = new InputThread(_reader, new InputThreadObserver());
                _in.start();

                Log.i(LOG_TAG, "End");
            } catch (UnknownHostException e) {
                Log.i(LOG_TAG, "UnknownHostException");
            } catch (IOException e) {
                Log.i(LOG_TAG, "IOException");
            }
        }
    }).start();
}

The creation of the socket is performed in a new thread, otherwise the execution freezes for few seconds.

If I set the variable _server to an existing host (for example www.google.com) everything goes all right. But if I set the _server variable to an host that does not exist (for example asd.asd) I really expect “UnknownHostException” to be printed in the logger. This does not happen (but the _socket variable is null). It just prints “Beginning” (and not “End”). Any Idea?

EDIT:

The variables are declared like this:

private String _server;
private Socket _socket;
private int _port;
private BufferedWriter _writer;
private BufferedReader _reader;
private InputThread _in;

EDIT:

I’m trying this:

public void startConnection() {
    new Thread(new Runnable() {
        @Override
        public void run() {
            try {
                Log.i(LOG_TAG, "Beginning");

                _socket = new Socket(_server, _port);

                if (_socket == null)
                    Log.i(LOG_TAG, "NULL SOCKET! (test 1)");                        

            } catch (Exception e) {
                Log.i(LOG_TAG, "EXCEPTION!");
            }

            if (_socket == null)
                Log.i(LOG_TAG, "NULL SOCKET! (test 2)");
        }
    }).start();
}

Don’t know why but the output is only:

Beginning

EDIT:

After 3 minutes and 13 seconds waiting i finally got:

EXCEPTION!
NULL SOCKET! (test 2)

Is that normal? Shouldn’t the UnknownHostException be thrown immediatly?

Answer 1

Looking at the API docs, if _server is a String, then you’ll get an UnknownHost exception. If it’s any of the other possibilities, you won’t.
In particular this signature will create the exception:

Socket(String host,
          int port)
   throws UnknownHostException,
          IOException