Q:

Remove Google Calendar custom property with java library

I am trying to remove some properties that I have stored in events. It works fine with direct API call:
PATCH https://www.googleapis.com/calendar/v3/calendars/calendarId/events/eventId
{
  "extendedProperties": {
    "private": {
      "petsAllowed": null
    }
  }
}

Example is taken from here: https://developers.google.com/calendar/extended-properties#deleting
But, it does nothing when I use java library for it:
PATCH 
ExtendedProperties extendedProperties = new ExtendedProperties();
extendedProperties.getShared().putIfAbsent(key, null);
originalEvent.setExtendedProperties(extendedProperties); 

After the patch, I still have old custom properties not deleted, even though I sent null values for their keys. 
I suspect that it's general mechanism problem that stands behind processing PATCH requests by Google Java Library. It might cut all the null values. 
Do you know the workaround for me to delete properties? I can't use UPDATE since I don't have enough data to fill out the object for this operation. 

A:

Patch only uodates the values you send.
Do a file.get and remove the record that you don't want not just the text.
then preform the patch useing this object.

