Getting a 400 response code on droplet create

While I know there is a community Java based API I have been trying to create a droplet via my own simple app but receive a 400 response code. Please could someone tell me what’s wrong with my code.

package code;

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

public class CreateDroplet {

	public static void main(String[] args) {
	    String urlString = "https://api.digitalocean.com/v2/droplets";
	      String newDroplet = "{'name' : 'ic2gb1'";
	      newDroplet += ", 'region' : 'lon1'";
	      newDroplet += ", 'size' : '2gb'";
	      newDroplet += ", 'image' : 12079764";
	      newDroplet += ", 'ssh_keys' : null";
	      newDroplet += ", 'backups' : true";
	      newDroplet += ", 'ipv6' : false";
	      newDroplet += ", 'user_data' : null";
	      newDroplet += ", 'private_networking'	: false";
				newDroplet += '}';
		URL url;
		try {
			url = new URL(urlString );
			HttpURLConnection conn = (HttpURLConnection) url.openConnection();
			conn.setRequestMethod("POST");
		    conn.setDoOutput(true);
		    conn.setRequestProperty ("Authorization", "Bearer *****************************************************************");
		    conn.setRequestProperty("Content-Type", "application/json");
		    DataOutputStream writer = new DataOutputStream(conn.getOutputStream());

			writer.writeBytes(newDroplet);
		    writer.flush();
		    int responseCode = conn.getResponseCode();
			System.out.println("responseCode: + responseCode));
		    String line;
		    BufferedReader reader = new BufferedReader(new 
		                                     InputStreamReader(conn.getInputStream()));
		    while ((line = reader.readLine()) != null) {
		      System.out.println(line);
		    }
		    writer.close();
		    reader.close();
		} catch (MalformedURLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}

}