Those of you with a GMail account might like this. It retrieves the GMail
Atom feed of you inbox status using the Rome Syndication libraries (Grab Rome 0.4 and Rome Fetcher 0.4 from http://rome.dev.java.net). You'll need to edit the BasicAuthenticator
class to set your username and password.

Gmail currently doesn't support conditional-gets or ETags, so unfortunately
it has to retrieve the entire feed each time.

public class Main {       
	public static void main(String args[] ) throws IllegalArgumentException, 
	MalformedURLException, IOException, FeedException, FetcherException {
		FeedFetcherCache feedInfoCache = HashMapFeedInfoCache.getInstance();
		FeedFetcher fetcher = new HttpURLFeedFetcher(feedInfoCache);
		java.net.Authenticator.setDefault(new BasicAuthenticator()); // turn on authentication
		SyndFeed feed = fetcher.retrieveFeed(new URL("https://gmail.google.com/gmail/feed/atom"));
		System.out.println(feed.getTitle());
		int feedSize = feed.getEntries().size();
		System.out.println("Contains " + feedSize + " items");
		for (Iterator iter = feed.getEntries().iterator(); iter.hasNext(); )
		{
			SyndEntry entry = (SyndEntry) iter.next();
			System.out.println(entry.getTitle());
			System.out.println("\t excerpt: " +
					entry.getDescription().getValue());
		}
		while (true) {
			try {
				Thread.sleep(1000 * 60 * 10); // check every 10 minutes
			} catch (InterruptedException e) {
				// ignore } System.err.print("Retrieving..");
				feed = fetcher.retrieveFeed(new
						URL("https://gmail.google.com/gmail/feed/atom"));
				System.err.println("Done.");
				int newFeedSize = feed.getEntries().size();
				// note that this won't detect new items if the feed size is at maximum
				if (feedSize != newFeedSize) {
					System.out.println("New messages detected. There are now " +
							newFeedSize + " items");
					int itemsToShow = newFeedSize - feedSize;                   
					int count = 0;
					for (Iterator iter = feed.getEntries().iterator();
					iter.hasNext();) {
						SyndEntry entry = (SyndEntry) iter.next();
						System.out.println(entry.getTitle());
						System.out.println("\t excerpt: " +
								entry.getDescription().getValue());
						count++;
						if (count >= itemsToShow) {
							break;
						}
					}                  
					feedSize = newFeedSize;
				}
			}
		}           
		static class BasicAuthenticator extends Authenticator {
			/**
			 * @see java.net.Authenticator#getPasswordAuthentication()
			 */
			protected PasswordAuthentication getPasswordAuthentication() {
				if ("gmail.google.com".equals(getRequestingHost())) {
					return new PasswordAuthentication("user.name", "password".toCharArray());
				} else {
					return null;
				}
			}
		}
	}