Thank you so much for your project. It's great. I am trying to use your project to send Alexa proactive event message. The sample code you have given is giving me an error on line -

event.getEvent().getPayload().getMessageGroup().getCreator().setName("Test");

Error by eclipse - Multiple markers at this line

• Syntax error on token "getEvent", Identifier expected after this token
• Syntax error on token ".", { expected

Below is what I am using from your example:
AlexaProactiveEventSenderClient client = new AlexaProactiveEventSenderClient(clientId, secretId);
ProactiveEvent event = new ProactiveEvent();
event.getEvent().getPayload().getMessageGroup().getCreator().setName("Test");
URLRegion urlRegion = new URLRegion();
urlRegion.setRegion(Region.NA);
urlRegion.setEnvironment(Environment.DEV);
client.sendProactiveEvent(event, urlRegion);