SlackAttachment.setTimestamp(Date date) throws NullPointerException

[bubu333gh]

Null-check is needed for the setter with Date param because mappers like Mapstruct are mapping null value to it. I had to make a workaround in my mapper like this:

@mapping(target = "timestamp", expression = "java(slackAttachment.getTimestamp() == null ? null : slackAttachment.getTimestamp().getTime() / 1000L)")