SDN 4 missing relationships in the graph - neo4j

Question

When I store my Neo4j nodes to the Neo4j graph, only nodes are stored (no relationships). Does anyone can point me to right direction what i am missing there?
here are my nodes
#NodeEntity public class Game extends AbstractEntity{
public Long timestamp;
public double total_pot_size;
public int flop;
public int turn;
public int river;
#Relationship(type = "ROUND")
public Set<Round> rounds;
#Relationship(type = "OUTCOME")
public Set<Outcome> outcomes;
public Game() {
super();
}
public void add(Outcome outcome) {
if (outcomes == null) {
outcomes = new HashSet<Outcome>();
}
outcomes.add(outcome);
}
public void add(Round round) {
if (rounds == null) {
rounds = new HashSet<Round>();
}
rounds.add(round);
}
}
and
#NodeEntity public class Player extends AbstractEntity {
public String name;
public String platform;
#Relationship(type = "PARTICIPATION", direction = Relationship.OUTGOING)
public Set<Participation> involved_games;
#Relationship(type = "OWNS")
public Set<Statistics> statistics;
public Player() {
super();
}
public void participate(Participation involved_game) {
if (involved_games == null) {
involved_games = new HashSet<Participation>();
}
involved_games.add(involved_game);
}
public void add(Statistics stat) {
if (statistics == null) {
statistics = new HashSet<>();
}
statistics.add(stat);
}
}
here is the code i use to store my data.
// create or get a new game in database
Game game = gameRepo.save( DataUtil.createGame(gi) );
// get the player involved to the game
List<Player> players = gi.getPlayers();
// for each player involved to the game...
for (Player player : players) {
org.quazar.data.domain.Player p = store(player);
// relationship participation
p.participate(DataUtil.createParticipation(p, game, player));
// set the outcome of the players
game.add(DataUtil.createOutcome(game, p, gi, player));
playerRepo.save(p);
}
gameRepo.save( game );
the store(player) method saves or retrieve (if not new) a player, which works properly. DataUtil.createParticipation and DataUtil.createOutcome methods creates new relationships (g.e. new Outcome()) and set the properties.
When running my application i do not get any exceptions, but in the graph i miss my relationships.
I did not listed all the nodes (e.g. Statistics) because right now i do not use them in my model, could that cause the problem?
Here are some relationships:
#RelationshipEntity(type = "PARTICIPATION")
public class Participation extends AbstractEntity {
#StartNode
public Player player;
#EndNode
public Game game;
#Property
public double bankroll;
#Property
public int holecards;
#Property
public byte position;
public Participation () {
super();
}
}
and
#RelationshipEntity(type = "OUTCOME")
public class Outcome extends AbstractEntity {
#StartNode
public Game game;
#EndNode
public Player player;
#Property
public String type;
#Property
public String round;
#Property
public double pot_size;
#Property
public double ante;
#Property
public int holecards;
#Property
public String bestHand;
#Property
public int bestHandrank;
public Outcome() {
super();
}
}