Google Drive API append file?

// Copyright 2018 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// [START drive_quickstart]
import java.io.BufferedWriter;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.security.GeneralSecurityException;
import java.util.Collections;
import java.util.List;
import com.google.api.client.auth.oauth2.Credential;
import com.google.api.client.extensions.java6.auth.oauth2.AuthorizationCodeInstalledApp;
import com.google.api.client.extensions.jetty.auth.oauth2.LocalServerReceiver;
import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow;
import com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets;
import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.client.util.store.FileDataStoreFactory;
import com.google.api.services.drive.Drive;
import com.google.api.services.drive.DriveScopes;
import com.google.api.services.drive.model.File;
import com.google.api.services.drive.model.FileList;

public class DriveQuickstart {
    private static final String APPLICATION_NAME = "Google Drive API Java Quickstart";
    private static final JsonFactory JSON_FACTORY = JacksonFactory.getDefaultInstance();
    private static final String TOKENS_DIRECTORY_PATH = "tokens";
    private static String fileId = "super_secret_string";
    private static final String OUTPUT = "super_secret_path";

    /**
     * Global instance of the scopes required by this quickstart.
     * If modifying these scopes, delete your previously saved credentials/ folder.
     */
    private static final List<String> SCOPES = Collections.singletonList(DriveScopes.DRIVE); //DONT USE THIS SCOPE IN PRODUCTION!
    private static final String CREDENTIALS_FILE_PATH = "/credentials.json";

    /**
     * Creates an authorized Credential object.
     * @param HTTP_TRANSPORT The network HTTP Transport.
     * @return An authorized Credential object.
     * @throws IOException If the credentials.json file cannot be found.
     */
    private static Credential getCredentials(final NetHttpTransport HTTP_TRANSPORT) throws IOException {
        // Load client secrets.
        InputStream in = DriveQuickstart.class.getResourceAsStream(CREDENTIALS_FILE_PATH);
        GoogleClientSecrets clientSecrets = GoogleClientSecrets.load(JSON_FACTORY, new InputStreamReader(in));

        // Build flow and trigger user authorization request.
        GoogleAuthorizationCodeFlow flow = new GoogleAuthorizationCodeFlow.Builder(
                HTTP_TRANSPORT, JSON_FACTORY, clientSecrets, SCOPES)
                .setDataStoreFactory(new FileDataStoreFactory(new java.io.File(TOKENS_DIRECTORY_PATH)))
                .setAccessType("offline")
                .build();
        return new AuthorizationCodeInstalledApp(flow, new LocalServerReceiver()).authorize("user");
    }

    public static void main(String... args) throws IOException, GeneralSecurityException {
        // Build a new authorized API client service.
        final NetHttpTransport HTTP_TRANSPORT = GoogleNetHttpTransport.newTrustedTransport();
        Drive service = new Drive.Builder(HTTP_TRANSPORT, JSON_FACTORY, getCredentials(HTTP_TRANSPORT))
                .setApplicationName(APPLICATION_NAME)
                .build();

        // Print the names and IDs for up to 10 files.
        FileList result = service.files().list()
                .setPageSize(10)
                .setFields("nextPageToken, files(id, name)")
                .execute();
        List<File> files = result.getFiles();
        if (files == null || files.isEmpty()) {
            System.out.println("No files found.");
        } else {
            System.out.println("Files:");
            for (File file : files) {
                System.out.printf("%s (%s)\n", file.getName(), file.getId());
            }
        }
        //Download the file from it's known ID
        FileOutputStream fos = new FileOutputStream(OUTPUT);
        service.files().export(fileId, "text/plain").executeMediaAndDownloadTo(fos);
        //Append some data to the file
        FileWriter fw = new FileWriter(OUTPUT, true);
        BufferedWriter bw = new BufferedWriter(fw);
        bw.newLine();
        bw.write("Goodbye, World!");
        bw.newLine();
        bw.close();

    }
}
// [END drive_quickstart]