NullPointerException on ManyToMany association at line org.hibernate.type.AbstractType.getHashCode(AbstractType.java:136) -------------------------------------------------------------------------------------------------------------------------- Key: HHH-4469 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-4469 Project: Hibernate Core Issue Type: Bug Components: core Affects Versions: 3.3.2 Environment: 2009-10-01 13:27:28,062 INFO [org.hibernate.cfg.annotations.Version] - Hibernate Annotations 3.4.0.GA 2009-10-01 13:27:28,078 INFO [org.hibernate.cfg.Environment] - Hibernate 3.3.2.GA 2009-10-01 13:27:28,078 INFO [org.hibernate.cfg.Environment] - hibernate.properties not found 2009-10-01 13:27:28,078 INFO [org.hibernate.cfg.Environment] - Bytecode provider name : javassist 2009-10-01 13:27:28,078 INFO [org.hibernate.cfg.Environment] - using JDK 1.4 java.sql.Timestamp handling 2009-10-01 13:27:28,141 INFO [org.hibernate.annotations.common.Version] - Hibernate Commons Annotations 3.1.0.GA 2009-10-01 13:27:28,141 INFO [org.hibernate.ejb.Version] - Hibernate EntityManager 3.3.1.GA Reporter: Sachin Mishra Attachments: hibernate-log.txt, hibernate-log.txt NullPointer Exception gets thrown on manytomany association when using composite key. Following the example from site http://boris.kirzner.info/blog/archives/2008/07/19/hibernate-annotations-... Loading the product entity correctly loads everything as expected but saving new product record doesn't work when using the composite keys. Item.java @Entity @Table(name="item") public class Item implements Serializable { private Integer id; private String name; private List<ProductItem> productItems = new LinkedList<ProductItem>(); private static Logger logger = Logger.getLogger(Item.class); /** * @return the id */ @Id @GeneratedValue(strategy=GenerationType.AUTO) @Column(name="item_id") public Integer getId() { return id; } /** * @param id the id to set */ public void setId(Integer id) { this.id = id; } /** * @return the name */ public String getName() { return name; } /** * @param name the name to set */ public void setName(String name) { this.name = name; } /** * @return the productItems */ @OneToMany(fetch=FetchType.LAZY,mappedBy="pk.item",cascade={CascadeType.ALL}) @Cascade({org.hibernate.annotations.CascadeType.ALL}) public List<ProductItem> getProductItems() { return productItems; } /** * @param productItems the productItems to set */ public void setProductItems(List<ProductItem> productItems) { this.productItems = productItems; } @Override public int hashCode() { int result; result = (this.id != null ? id.hashCode() : 0); result = 31 * result + (name != null ? name.hashCode() : 0); return result; } @Override public boolean equals(Object obj) { if (obj == null) { return false; } if (getClass() != obj.getClass()) { return false; } final Item other = (Item) obj; if (this.id != other.id && (this.id == null || !this.id.equals(other.id))) { return false; } if ((this.name == null) ? (other.name != null) : !this.name.equals(other.name)) { return false; } return true; } } Product.java @Entity @Table(name="product") public class Product implements Serializable { private static Logger logger = Logger.getLogger(Product.class); private Integer id; private String name; private String description; private double regularPrice; private List<ProductItem> productItems = new LinkedList<ProductItem>(); /** * @return the id */ @Id @GeneratedValue(strategy=GenerationType.AUTO) @Column(name="prod_id") public Integer getId() { return id; } /** * @return the name */ @Column(name="prod_name") public String getName() { return name; } /** * @param name the name to set */ public void setName(String name) { this.name = name; } /** * @return the productItems */ @OneToMany(fetch=FetchType.LAZY,mappedBy="pk.product",cascade={CascadeType.ALL}) @Cascade({org.hibernate.annotations.CascadeType.ALL}) public List<ProductItem> getProductItems() { return productItems; } /** * @param productItems the productItems to set */ public void setProductItems(List<ProductItem> productItems) { this.productItems = productItems; } /** * @param id the id to set */ public void setId(Integer id) { this.id = id; } @Override public int hashCode() { int result; result = (id != null ? id.hashCode() : 0); result = 31 * result + (name != null ? name.hashCode() : 0); return result; } @Override public boolean equals(Object obj) { if (obj == null) { return false; } if (getClass() != obj.getClass()) { return false; } final Product other = (Product) obj; if (this.id != other.id && (this.id == null || !this.id.equals(other.id))) { return false; } if ((this.name == null) ? (other.name != null) : !this.name.equals(other.name)) { return false; } return true; } ProductItem.java @Entity @Table(name = "productItem") @AssociationOverrides({ @AssociationOverride(name = "pk.product", joinColumns = @JoinColumn(name = "product_id")), @AssociationOverride(name = "pk.item", joinColumns = @JoinColumn(name = "item_id")) }) public class ProductItem implements Serializable{ private static Logger logger = Logger.getLogger(ProductItem.class); private ProductItemPk pk ; /** * @return the item */ @Transient public Item getItem() { return getPk().getItem(); } /** * @param item the item to set */ public void setItem(Item item) { getPk().setItem(item); } /** * @return the Product */ @Transient public Product getProduct() { return getPk().getProduct(); } /** * @param Product the Product to set */ public void setProduct(Product Product) { getPk().setProduct(Product); } /** * @return the pk */ @EmbeddedId public ProductItemPk getPk() { return pk; } /** * @param pk the pk to set */ public void setPk(ProductItemPk pk) { this.pk = pk; } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; ProductItem that = (ProductItem) o; if (getPk() != null ? !getPk().equals(that.getPk()) : that.getPk() != null) return false; return true; } @Override public int hashCode() { return (getPk() != null ? getPk().hashCode() : 0); } ProductItemPk.java @Embeddable public class ProductItemPk implements Serializable{ private static Logger logger = Logger.getLogger(ProductItemPk.class); private Item item; private Product product; /** * @return the item */ @ManyToOne(optional=false) public Item getItem() { return item; } /** * @param item the item to set */ public void setItem(Item item) { this.item = item; } /** * @return the product */ @ManyToOne(optional=false) public Product getProduct() { return product; } /** * @param product the product to set */ public void setProduct(Product product) { this.product = product; } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; ProductItemPk that = (ProductItemPk) o; if (item != null ? !item.equals(that.item) : that.item != null) return false; if (product != null ? !product.equals(that.product) : that.product != null) return false; return true; } @Override public int hashCode() { logger.error("productitemPK hashcode called"); int result; result = (item != null ? item.hashCode() : 0); result = 31 * result + (product != null ? product.hashCode() : 0); return result; }