code: public MessageMgr build(){
  		if(this.messageHandlers.size()==0){
  			this.buildErrors.addError("no message handlers set");
  			return null;
  		}
  		return new MessageMgr(this.appID, this.messageHandlers, this.doCollectMessages);
  	}
docs: Builds a {@link MessageMgr}.
  @return an new manager if all required parameters are set, null if not with errors being logged