docs: public boolean getBoolean(int columnIndex) {
  		Object fieldValue = data[columnIndex];
  		if (fieldValue == null) {
  			return Boolean.FALSE;
  		}
  		if (fieldValue instanceof Boolean) {
  			return (Boolean) fieldValue;
  		}
  		throw new DBFException("Unsupported type for Boolean at column:" + columnIndex + " "
  				+ fieldValue.getClass().getCanonicalName());
  	}