UpdateEventsWorker.java

//we create a class that extends Worker
public class UpdateEventsWorker extends Worker {
  //here we define the constants for the remote URL LiveData tag and 
  //the filename of the file we'll be exporting the JSON to
  private static final String REMOTE_URL = "REMOTE_URL";
  private static final String JSON_RESULT = "JSON_STRING";
  
 public UpdateEventsWorker(@NonNull Context context, @NonNull WorkerParameters params) {
  super(context, params);
 }
  
  @NonNull
  @Override
  public Result doWork() {
    //firstly, we get the livedata and store it in a String
    Data input = getInputData();
    final String remoteUrl = input.getString(REMOTE_URL);
    
    //then we try to fetch the remote JSON file and store it into a String
    String jsonString = null;
    try {
      jsonString = getJSON(remoteUrl);
    } catch (IOException e) {
      e.printStackTrace();
    }
    
    //if this succeeds, we store it in a file since LiveData is limited
    //to 10KB for some reason; I'm using a PrintWriter instead of just 
    //accessing the FileInputStream directly since I need the UTF-8 encoding
    if (!TextUtils.isEmpty(jsonString) && jsonString.length() > 50) {
      try(PrintWriter printWriter = new PrintWriter(new File(getApplicationContext()
                                            .getFilesDir(), JSON_RESULT), "UTF-8")){
        printWriter.write(jsonString);
      } catch (IOException e) {
        e.printStackTrace();
      }
      
      //we return SUCCESS if all is well
      return Result.SUCCESS;
    } 
    
    //otherwise we return FAILURE so we know something went wrong
    else return Result.FAILURE;
  }
}