A sample to shorten url using Google URL Shortener API.

gistfile1.java

package jp.roundrop.util;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;

public final class GoogleUrlShortener {

    public static String shorten(String longUrl) {
        if (longUrl == null) {
            return longUrl;
        }
        
        try {
            URL url = new URL("http://goo.gl/api/url");
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setDoOutput(true);
            connection.setRequestMethod("POST");
            connection.setRequestProperty("User-Agent", "toolbar");

            OutputStreamWriter writer = new OutputStreamWriter(connection.getOutputStream());
            writer.write("url=" + URLEncoder.encode(longUrl, "UTF-8"));
            writer.close();

            BufferedReader rd = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            StringBuilder sb = new StringBuilder();
            String line = null;
            while ((line = rd.readLine()) != null) {
                sb.append(line + '\n');
            }
            String json = sb.toString();
            return json.substring(json.indexOf("http"), json.indexOf("\"", json.indexOf("http")));
        } catch (MalformedURLException e) {
            return longUrl;
        } catch (IOException e) {
            return longUrl;
        }
    }

}

This is easy and fine, but it has some daily requests limits.

not working your program just return same url ... not shorten url

This doesn't work. It returns the same input URL.

It returns the same input URL "longUrl "

Google shortner api is now deprecated so this will no longer work.
Look at:
https://firebase.google.com/docs/dynamic-links/create-links

It's thrown the IOException error.