Child primary key not updated by hibernate - spring

Question

I'm using hibernate and spring data to save entities in my database. I'm attaching child elements to the parent and vice versa. Everything is saved correctly in the database, as well the child instances.
After calling save method again, the child elements get saved twice. I found out, that the reason is, that the framework does not update the childrens Id after persisting. It is always zero. Parent ID got updated correctly.
Any idea how to solve that?
Receipt.java:
#Entity
#javax.persistence.Table(name = "receipts")
public class Receipt {
private int id;
/*
* [...]
*/
#Id
#Column(name = "id")
#GeneratedValue(strategy = GenerationType.IDENTITY)
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
#OneToMany(fetch = FetchType.EAGER,cascade = CascadeType.ALL)
#JoinColumn(name = "receipt_id",referencedColumnName = "id")
private List<ReceiptItem> getReceiptItemList() {
return receiptItemList;
}
private void setReceiptItemList(List<ReceiptItem> receiptItemList) {
this.receiptItemList = receiptItemList;
}
/*
* [...]
*/
}
ReceiptItem.java:
#Entity
#Table(name = "receipt_items")
public class ReceiptItem {
private int id;
/*
* [...]
*/
#Id
#Column(name = "id")
#GeneratedValue(strategy = GenerationType.IDENTITY)
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
#ManyToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "receipt_id")
public Receipt getReceipt() {
return receipt;
}
public void setReceipt(Receipt receipt) {
this.receipt = receipt;
}
}
Saving:
item = new ReceiptItem();
item.setReceipt(receipt);
receipt.getReceiptItemList().add(item);
// this should create the new ReceiptItem instance
receiptService.save(receipt);
System.out.println("ItemId: "+item.getId()); //but the id is still 0
// calling save method twice results in a second entry in the database
// instead of updating the previously inserted one
receiptService.save(receipt);
System.out.println("ItemId: "+item.getId());
Output:
ItemId: 0
ItemId: 0