Update if the document already exists in Azure Cosmos DB Java SDK, create new if it does not exist

package com.microsoft.azure.documentdb.sample;

import java.util.Date;
import java.util.Iterator;

import com.google.gson.Gson;
import com.google.gson.JsonObject;
import com.microsoft.azure.documentdb.ConnectionMode;
import com.microsoft.azure.documentdb.ConnectionPolicy;
import com.microsoft.azure.documentdb.ConsistencyLevel;
import com.microsoft.azure.documentdb.Document;
import com.microsoft.azure.documentdb.DocumentClient;
import com.microsoft.azure.documentdb.FeedOptions;
import com.microsoft.azure.documentdb.FeedResponse;
import com.microsoft.azure.documentdb.ResourceResponse;

public class HelloCosmodDB002UpdateDocument {

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

		// Azure Cosmos DB Libraries for Java
		// https://docs.microsoft.com/ja-jp/java/api/overview/azure/cosmosdb?view=azure-java-stable

		String host = "{yourhost}";
		String database_id = "{your_database}";
		String collection_id = "{your_collection}";

		// Get key from Azure Web Console
		// read write key
		String key = "{your_key}";

		String endPoint = "https://" + host + ".documents.azure.com:443";

		ConnectionPolicy policy = new ConnectionPolicy();
		policy.setConnectionMode(ConnectionMode.DirectHttps);

		try (DocumentClient client = new DocumentClient(endPoint, key, ConnectionPolicy.GetDefault(),
				ConsistencyLevel.Session)) {

			// Name? ID?
			String collectionLink = String.format("/dbs/%s/colls/%s", database_id, collection_id);

			JsonObject json;

			FeedOptions options = new FeedOptions();
			options.setEnableCrossPartitionQuery(true);

			FeedResponse<Document> res = client.queryDocuments(collectionLink, "SELECT * FROM c WHERE c.id=\"1000\"",
					options, "{your_pkey}");

			Iterator<Document> itr = res.getQueryIterator();

			if (itr.hasNext()) {
				Document doc = itr.next();
				Gson gson = new Gson();
				json = gson.fromJson(doc.toJson(), JsonObject.class);
			} else {
				json = new JsonObject();
				json.addProperty("id", "1000");
			}

			json.addProperty("text2", "This is test for update.");
			json.addProperty("lastupdate", System.currentTimeMillis());

			Document d = new Document(json.toString());

			ResourceResponse<Document> response = client.upsertDocument(collectionLink, d, null, false);
			client.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}