You should probably cite what you're quoting.  In any event, as I
stated, the sample at the URL above does not use TCP port 7, it uses TCP
port 13, the 'daytime' service which seems rarely supported anymore.

A better implementation using the 'echo' service might use UDP instead,
since it doesn't require a connection to be established.

Ok, some more testing done, I now think the problem is not the timeout
being ignored, but the time for executing the connect: doing something
like

[...]
  Socket theSock = new Socket();
  start0 = System.currentTimeMillis();
  theSock.connect(sockaddr, timeoutMs);
  end0 = System.currentTimeMillis();

  theSock = new Socket();
  start1 = System.currentTimeMillis();
  theSock.connect(sockaddr, timeoutMs);
  end1 = System.currentTimeMillis();
[...]

sometimes returns big values (>4000ms) for (end0 - start0) and usually
values in the expected range for (end1 - start1). Is this a problem of
JIT-Compiling?

However, looking at
http://java.sun.com/j2se/1.5.0/docs/guide/nio/example/Ping.java
I´ve managed to get a solution that´s working for me atm, based on a
thread observing finishConnect() on a SocketChannel.
Please excuse any bad coding style (it´s my first week on java ;) -
remarks very welcome.

-- 8< -------------------------------------------------------------
package myping;

import java.io.*;
import java.net.*;
import java.nio.channels.*;

public class Ping {
   
   private static int timeout; // Timeout in ms for pinging
   private static Target t;
   private static SocketChannel sc;
   
   // Representation of a ping target
   private static class Target {
       
       public InetSocketAddress address;
       public SocketChannel channel;
       public long connectStart;
       public long connectFinish = 0;
       public Exception failure = null;
       
       public Target(String host, int port) throws IOException {
           address = new
InetSocketAddress(InetAddress.getByName(host), port);
       }
       
       public long getPing() throws IOException, InterruptedException
{
           if (connectFinish != 0)
               return connectFinish - connectStart;
           else if (failure != null)
               if (failure instanceof IOException)
                   throw (IOException) failure;
               else if (failure instanceof InterruptedException)
                   throw (InterruptedException) failure;
               else
                   return -2; //should not happen
           else
               return -1; //Timed out
       }
   }
   
   // Thread for connecting to target
   private static class connector extends Thread {
       
       private volatile boolean shutdown = false;
       
       public connector() {
           setName("connector");
       }
       public void shutdown() {
           shutdown = true;
       }
       public void run() {
           for (;;) {
               if (shutdown) {
                   return;
               }
               // Attempt to complete the connection sequence
               try {
                   if (sc.finishConnect()) {
                       t.connectFinish = System.currentTimeMillis();
                       sc.close();
                       return;
                   }
               } catch (IOException x) {
                   try {
                       sc.close();
                   } catch (IOException xx) {
                       t.failure = xx;
                   }
                   t.failure = x;
               }
           }
       }
   }
   
   public static long ping(String host, int port, int timeout) throws
InterruptedException, IOException {
       
       Ping.t = new Target(host, port);
       Ping.timeout = timeout;
       
       // Initiate a connection sequence to the given target
       Ping.sc = null;
       // Open the channel, set it to non-blocking, initiate connect
       sc = SocketChannel.open();
       sc.configureBlocking(false);
       sc.connect(t.address);
       // Record the time we started
       t.connectStart = System.currentTimeMillis();
       t.channel = sc;

       connector conn = new connector();
       conn.start();
       conn.join(timeout);
       conn.shutdown();

       sc.close();
       return t.getPing();
   }
   
   public static void main(String[] args) throws
InterruptedException, IOException {
       
       System.out.println(ping("123.123.123.123", 7, 500)); //host,
port, timeout in ms
   }
   
}
-- 8< -------------------------------------------------------------

cheers,
guenter. <gd--acm-org>