code: @Override
  	public void encodeNullToNull(Writer writer, List<Integer> obj) throws IOException {
  		if (obj == null) {
  			writer.write("null");
  			return;
  		}
  
  		startArray(writer);
  
  		int size = obj.size();
  		for (int i = 0; i < size; i++) {
  			JsonUtil.put(writer, (int) obj.get(i));
  			if (i + 1 < size) {
  				addSeparator(writer);
  			}
  		}
  
  		endArray(writer);
  	}
docs: {@inheritDoc}