title: org.hibernate.PersistentObjectException: detached entity passed to persist
body: <p>I had successfully written my first master child example with hibernate. After few days I took it again and upgraded some libraries. No sure what did I do but I could never make it run again. Would somebody help my figure out what is wrong in code that is returning following error message:</p>
  
  <pre><code>org.hibernate.PersistentObjectException: detached entity passed to persist: example.forms.InvoiceItem
      at org.hibernate.event.def.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:127)
      at org.hibernate.impl.SessionImpl.firePersist(SessionImpl.java:799)
      at org.hibernate.impl.SessionImpl.persist(SessionImpl.java:791)
      .... (truncated)
  </code></pre>
  
  <p>hibernate mapping:</p>
  
  <pre><code>&lt;hibernate-mapping package="example.forms"&gt;
      &lt;class name="Invoice" table="Invoices"&gt;
          &lt;id name="id" type="long"&gt;
              &lt;generator class="native" /&gt;
          &lt;/id&gt;
          &lt;property name="invDate" type="timestamp" /&gt;
          &lt;property name="customerId" type="int" /&gt;
          &lt;set cascade="all" inverse="true" lazy="true" name="items" order-by="id"&gt;
              &lt;key column="invoiceId" /&gt;
              &lt;one-to-many class="InvoiceItem" /&gt;
          &lt;/set&gt;
      &lt;/class&gt;
      &lt;class name="InvoiceItem" table="InvoiceItems"&gt;
          &lt;id column="id" name="itemId" type="long"&gt;
              &lt;generator class="native" /&gt;
          &lt;/id&gt;
          &lt;property name="productId" type="long" /&gt;
          &lt;property name="packname" type="string" /&gt;
          &lt;property name="quantity" type="int" /&gt;
          &lt;property name="price" type="double" /&gt;
          &lt;many-to-one class="example.forms.Invoice" column="invoiceId" name="invoice" not-null="true" /&gt;
      &lt;/class&gt;
  &lt;/hibernate-mapping&gt;
  </code></pre>
  
  <p><strong>EDIT:</strong> InvoiceManager.java</p>
  
  <pre><code>class InvoiceManager {
  
      public Long save(Invoice theInvoice) throws RemoteException {
          Session session = HbmUtils.getSessionFactory().getCurrentSession();
          Transaction tx = null;
          Long id = null;
          try {
              tx = session.beginTransaction();
              session.persist(theInvoice);
              tx.commit();
              id = theInvoice.getId();
          } catch (RuntimeException e) {
              if (tx != null)
                  tx.rollback();
              e.printStackTrace();
              throw new RemoteException("Invoice could not be saved");
          } finally {
              if (session.isOpen())
                  session.close();
          }
          return id;
      }
  
      public Invoice getInvoice(Long cid) throws RemoteException {
          Session session = HbmUtils.getSessionFactory().getCurrentSession();
          Transaction tx = null;
          Invoice theInvoice = null;
          try {
              tx = session.beginTransaction();
              Query q = session
                      .createQuery(
                              "from Invoice as invoice " +
                              "left join fetch invoice.items as invoiceItems " +
                              "where invoice.id = :id ")
                      .setReadOnly(true);
              q.setParameter("id", cid);
              theInvoice = (Invoice) q.uniqueResult();
              tx.commit();
          } catch (RuntimeException e) {
              tx.rollback();
          } finally {
              if (session.isOpen())
                  session.close();
          }
          return theInvoice;
      }
  }
  </code></pre>
  
  <p>Invoice.java</p>
  
  <pre><code>public class Invoice implements java.io.Serializable {
  
      private Long id;
      private Date invDate;
      private int customerId;
      private Set&lt;InvoiceItem&gt; items;
  
      public Long getId() {
          return id;
      }
  
      public Date getInvDate() {
          return invDate;
      }
  
      public int getCustomerId() {
          return customerId;
      }
  
      public Set&lt;InvoiceItem&gt; getItems() {
          return items;
      }
  
      void setId(Long id) {
          this.id = id;
      }
  
      void setInvDate(Date invDate) {
          this.invDate = invDate;
      }
  
      void setCustomerId(int customerId) {
          this.customerId = customerId;
      }
  
      void setItems(Set&lt;InvoiceItem&gt; items) {
          this.items = items;
      }
  }
  </code></pre>
  
  <p>InvoiceItem.java</p>
  
  <pre><code>public class InvoiceItem implements java.io.Serializable {
  
      private Long itemId;
      private long productId;
      private String packname;
      private int quantity;
      private double price;
      private Invoice invoice;
  
      public Long getItemId() {
          return itemId;
      }
  
      public long getProductId() {
          return productId;
      }
  
      public String getPackname() {
          return packname;
      }
  
      public int getQuantity() {
          return quantity;
      }
  
      public double getPrice() {
          return price;
      }
  
      public Invoice getInvoice() {
          return invoice;
      }
  
      void setItemId(Long itemId) {
          this.itemId = itemId;
      }
  
      void setProductId(long productId) {
          this.productId = productId;
      }
  
      void setPackname(String packname) {
          this.packname = packname;
      }
  
      void setQuantity(int quantity) {
          this.quantity = quantity;
      }
  
      void setPrice(double price) {
          this.price = price;
      }
  
      void setInvoice(Invoice invoice) {
          this.invoice = invoice;
      }
  }
  </code></pre>
  
  <p><strong>EDIT:</strong> JSON object sent from client:</p>
  
  <pre><code>{"id":null,"customerId":3,"invDate":"2005-06-07T04:00:00.000Z","items":[
  {"itemId":1,"productId":1,"quantity":10,"price":100},
  {"itemId":2,"productId":2,"quantity":20,"price":200},
  {"itemId":3,"productId":3,"quantity":30,"price":300}]}
  </code></pre>
  
  <p><strong>EDIT:</strong> Some details:<br>
  I have tried to save invoice by following two ways:</p>
  
  <ol>
  <li><p>Manually fabricated above mentioned
  json object and passed it to fresh
  session of server. In this case absolutely 
  no activity has been made prior to calling 
  save method so there should not be any open session
  except the one opened in save method</p></li>
  <li><p>Loaded existing data by using
  getInvoice method and them passed same 
  data after removing key value. This too I believe
  should close the session before saving as
  transaction is being committed in getInvoice method.</p></li>
  </ol>
  
  <p>In both cases I am getting same error message that is forcing me to believe that something is wrong either with hibernate configuration file or entity classes or save method.  </p>
  
  <p><strong>Please let me know if I should provide more details</strong></p>