New Entity is created with every Persist JPA - jpa

Question

I just get started with JPA. I have an entity CustomerOrderEntity which has #OneToMany relation with another entity BeverageEntity. When I add the BeverageEntity to the CustomerOrderEntity a new entity is created of the type BeverageEntity and is persisted in the database as a new record. I do not want something like that I only need the CustomerOrderEntity to have the record of BeverageEntity and a new entity is not created for that inside the database.
These two entities are invoked from this class SalesManagement:
#Stateless
#Remote(SalesManagement.class)
public class SalesManagementBean implements SalesManagement {
#PersistenceContext(type = PersistenceContextType.TRANSACTION)
EntityManager em;
#Override
public void createOrder(CustomerOrder order) {
order.getOrderItems().forEach(item -> {
updateBeverageQuantity(item.getId(), item.getQuantity());
});
CustomerOrderEntity customerOrderEntity = new CustomerOrderEntity();
customerOrderEntity.setIssueDate(order.getIssueDate());
order.getOrderItems().forEach(item ->{
customerOrderEntity.addOrder(toEntity(item));
});
em.persist(customerOrderEntity);
}
public void updateBeverageQuantity(int b_id, int quantity) {
BeverageEntity beverageEntity = em.find(BeverageEntity.class, b_id);
if(beverageEntity != null) {
beverageEntity.setQuantity(beverageEntity.getQuantity() - quantity);
em.persist(beverageEntity);
}
}
public List<BeverageEntity> toBeverageEntity(List<Beverage> beverages) {
List<BeverageEntity> entities = new ArrayList<BeverageEntity>();
if(beverages != null && beverages.size() > 0) {
beverages.forEach(beverage -> {
BeverageEntity entity = new BeverageEntity();
entity.setName(beverage.getName());
entity.setManufacturer(beverage.getManufacturer());
entity.setQuantity(beverage.getQuantity());
entity.setPrice(beverage.getPrice());
entity.setIncentiveEntity(toIncentiveEntity(beverage.getIncentiveDTO()));
entities.add(entity);
});
return entities;
}
return null;
}
public IncentiveEntity toIncentiveEntity(IncentiveDTO incentiveDTO) {
if(incentiveDTO != null) {
IncentiveEntity entity = null;
return entity;
}
return null;
}
public BeverageEntity toEntity(Beverage b) {
BeverageEntity entity = new BeverageEntity();
entity.setName(b.getName());
entity.setManufacturer(b.getManufacturer());
entity.setQuantity(b.getQuantity());
entity.setPrice(b.getPrice());
entity.setIncentiveEntity(toIncentiveEntity(b.getIncentiveDTO()));
return entity;
}
}
I think the problem is in the method toBeverageEntity. But I am not sure about it.
The CustomerOrderEntity:
#Entity
public class CustomerOrderEntity {
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE)
private int id;
#Version
private int version;
private Date issueDate;
#OneToMany(cascade = CascadeType.PERSIST, fetch = FetchType.LAZY)
private List<BeverageEntity> beverageEntities;
public void addOrder(BeverageEntity beverageEntity) {
this.beverageEntities.add(beverageEntity);
}
public List<BeverageEntity> getBeverageEntities() {
return beverageEntities;
}
public void setBeverageEntities(List<BeverageEntity> beverageEntities) {
this.beverageEntities = beverageEntities;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public int getVersion() {
return version;
}
public void setVersion(int version) {
this.version = version;
}
public Date getIssueDate() {
return issueDate;
}
public void setIssueDate(Date issueDate) {
this.issueDate = issueDate;
}
}
The BeverageEntity:
#Entity
public class BeverageEntity implements Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE)
private int id;
private String name;
private String manufacturer;
private int quantity;
private double price;
#Version
private int version;
#ManyToOne(cascade = CascadeType.PERSIST, fetch = FetchType.LAZY)
private IncentiveEntity incentiveEntity;
public BeverageEntity() {
}
public BeverageEntity(String name, String manufacturer, int quantity, Double price, IncentiveEntity entity) {
this.name = name;
this.manufacturer = manufacturer;
this.quantity = quantity;
this.price = price;
this.incentiveEntity = entity;
}
public BeverageEntity(String name, String manufacturer, int quantity, Double price) {
this.name = name;
this.manufacturer = manufacturer;
this.quantity = quantity;
this.price = price;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getManufacturer() {
return manufacturer;
}
public void setManufacturer(String manufacturer) {
this.manufacturer = manufacturer;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
public int getVersion() {
return version;
}
public void setVersion(int version) {
this.version = version;
}
public int getQuantity() {
return quantity;
}
public void setQuantity(int quantity) {
this.quantity = quantity;
}
public IncentiveEntity getIncentiveEntity() {
return incentiveEntity;
}
public void setIncentiveEntity(IncentiveEntity incentiveEntity) {
this.incentiveEntity = incentiveEntity;
}
}

Answer 1

Found the problem it was in the method toBeverageEntity as pointed out in the comments I was creating a new entity that was wrong. I needed to use find because the entity is already in the database.
BeverageEntity entity = em.find(BeverageEntity.class, beverage.getId());
entities.add(entity);