A demo of shortened URL expansion using Apache HttpComponents (http://hc.apache.org/)

RedirectSpy.java

import com.google.common.base.Joiner;
import org.apache.http.HttpRequest;
import org.apache.http.HttpResponse;
import org.apache.http.ProtocolException;
import org.apache.http.client.methods.HttpHead;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.impl.client.DefaultRedirectStrategy;
import org.apache.http.protocol.HttpContext;

import java.io.IOException;
import java.net.URI;
import java.util.Deque;
import java.util.LinkedList;

public class RedirectSpy {
    public static class SpyStrategy extends DefaultRedirectStrategy {
        public final Deque<URI> history = new LinkedList<>();
        
        public SpyStrategy(URI uri) {
            history.push(uri);
        }
        
        @Override
        public HttpUriRequest getRedirect(
                HttpRequest request,
                HttpResponse response,
                HttpContext context) throws ProtocolException {
            HttpUriRequest redirect = super.getRedirect(request, response, context);
            history.push(redirect.getURI());
            return redirect;
        }
    }

    public static Deque<URI> expand(String uri) {
        try {
            HttpHead head = new HttpHead(uri);
            SpyStrategy spy = new SpyStrategy(head.getURI());
            DefaultHttpClient client = new DefaultHttpClient();
            client.setRedirectStrategy(spy);
            // FIXME: the following completely ignores HTTP errors:
            client.execute(head);
            return spy.history;
        }
        catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public static void main(String[] args) throws IOException {
        Joiner link = Joiner.on(" \u2190 ");
        for (String uri: args) {
            System.out.println(link.join(expand(uri)));
        }
    }
}

For instance:

$ java -cp ... RedirectSpy http://t.co/GKwKPqQ9KX http://t.co/D6VT308Yzz

http://blog.22tracks.com/on-to-the-next-chapter/ ← http://wv.ly/18LRVmO ← http://t.co/GKwKPqQ9KX
http://instagram.com/p/ZVz0x8vfMU/ ← http://t.co/D6VT308Yzz