Am i supposed to (able) to use "empty c++ class"?

[anonymous_user_6cf86672]

Hello there,
I am trying to create a hierarchical data read/write system and i will not expose this data classes to engine editor. So i want to use a basic c++ class (not a UObject).

i have three classes:

DataNodeM (basic c++ class, means not derived from anything)

UDataBoardM (derived from UObject)

AMyActor (derived from AActor)

even tho i dont expose anything from DataNodeM class, i keep getting engine crash.

MyActor.h

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "GameFramework/Actor.h"
#include "MyActor.generated.h"

class UDataBoardM;

UCLASS()
class EMPTYCLASSTEST_API AMyActor : public AActor
{
	GENERATED_BODY()

public:
	// Sets default values for this actor's properties
	AMyActor();

	// Called when the game starts or when spawned
	virtual void BeginPlay() override;
	virtual void EndPlay(const EEndPlayReason::Type EndPlayReason) override;

	// Called every frame
	virtual void Tick(float DeltaSeconds) override;

	UFUNCTION(Category = DataBoard, BlueprintCallable)
		UDataBoardM* GetDataBoard() { return FDataBoard; }
private:
	UDataBoardM* FDataBoard = NULL;
};

MyActor.cpp

// Fill out your copyright notice in the Description page of Project Settings.

#include "EmptyClassTest.h"
#include "DataBoardM.h"
#include "MyActor.h"


// Sets default values
AMyActor::AMyActor()
{
	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;

	FDataBoard = CreateDefaultSubobject<UDataBoardM>(TEXT("DataBoard"));
}

// Called when the game starts or when spawned
void AMyActor::BeginPlay()
{
	Super::BeginPlay();

}

void AMyActor::EndPlay(const EEndPlayReason::Type EndPlayReason)
{
	Super::EndPlay(EndPlayReason);
	FDataBoard->Clear();
}

// Called every frame
void AMyActor::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);

}

DataBoardM.h

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "UObject/NoExportTypes.h"
#include "DataBoardM.generated.h"

class DataNodeM;


UCLASS(meta = (BlueprintSpawnableComponent))
class EMPTYCLASSTEST_API UDataBoardM : public UObject
{
	GENERATED_BODY()
public:
	UDataBoardM();
	//static TCHAR NodeSeperator;

	//UFUNCTION(Category = DataBoard, BlueprintCallable)
	//	static TCHAR GetNodeSeperator() { return UDataBoardM::NodeSeperator; }

	//UFUNCTION(Category = Grip, BlueprintCallable)
	//	static void SetNodeSeperator(TCHAR newNodeSeperator) { UDataBoardM::NodeSeperator = newNodeSeperator; }

	UFUNCTION(Category = DataBoard, BlueprintCallable)
		void Clear();
protected:
	DataNodeM* GetRoot(bool create);
	DataNodeM* GetRoot() { return GetRoot(true); }
private:
	DataNodeM* FRoot = NULL;
};

DataBoardM.cpp

// Fill out your copyright notice in the Description page of Project Settings.

#include "EmptyClassTest.h"
#include "DataNodeM.h"
#include "DataBoardM.h"

//TCHAR UDataBoardM::NodeSeperator = '.';

UDataBoardM::UDataBoardM()
{
	FRoot = NULL;
}

DataNodeM* UDataBoardM::GetRoot(bool create)
{
	//if (create && (FRoot == NULL))
	//	FRoot = new DataNodeM();
	return FRoot;
}

void UDataBoardM::Clear()
{
	DataNodeM* root = GetRoot(false);
	if (root != NULL)
		root->Clear();
}

DataNodeM.h

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

/**
 * 
 */
class EMPTYCLASSTEST_API DataNodeM
{
public:
	DataNodeM();
	~DataNodeM();

	void Clear() {}
};

DataNodeM.cpp

// Fill out your copyright notice in the Description page of Project Settings.

#include "EmptyClassTest.h"
#include "DataNodeM.h"

DataNodeM::DataNodeM()
{
}

DataNodeM::~DataNodeM()
{
}

Level blueprint:

whenever i push play, engine crashes.

any help would be appreciated.