java http send a post request

/**
 * @author lautturi.com
 * Java example: how to send a post request in java http
 */

import java.util.*;
import java.io.*;
import java.net.*;

public class Lautturi {

	public static void main(String[] args) throws IOException {

		URL url = new URL("https://www.lautturi.com");
		String user_agent = "Mozilla/5.0";
		String post_params = "id=123";

		HttpURLConnection con = (HttpURLConnection) url.openConnection();
		con.setRequestMethod("POST");
		con.setRequestProperty("User-Agent", user_agent);

		// For POST only - START
		con.setDoOutput(true);
		OutputStream os = con.getOutputStream();
		os.write(post_params.getBytes());
		os.flush();
		os.close();
		// For POST only - END

		int responseCode = con.getResponseCode();
		System.out.println("POST Response Code :: " + responseCode);

		if (responseCode == HttpURLConnection.HTTP_OK) { // success
			BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
			String inputLine;
			StringBuffer response = new StringBuffer();

			while ((inputLine = in.readLine()) != null) {
				response.append(inputLine);
			}
			in.close();

			// print result
			System.out.println(response.toString());
		} else {
			System.out.println("Response Code " + responseCode);
		}

	}
}