My situation is the following:
I am mapping a simple one-to-many relationship I have done many times before successfully without too much thought. However yesterday after starting anew project and downloading the latest hibernate jars I experienced some strange behaviour when using JPA Annotations to map a one-to-many.
In a nutshell, the code works fine if the Annotation is placed at field level as opposed to the placing it above the getter, but fails if its placed on the getter...unless I explicitly declare the collection field implementation type rather than use the interface, e.g. HashSet instead of Set. My question is why cant I place the annotation above the getter and use an interface eg Set reference instead of a concrete implementation like HashSet as I have always done??
I can resolve the problem by either:
1) Placing all annotations at field level
2) Use the class implementation for collection/set type field references rather than the interface i.e. HashSet instead of Set, ArrayList instead of List and carry on placing the annotation above the getter.
But why is it a problem in the first place???
Here is the parent side:
@Entity
@Table(name="TEST")
public class Test extends BaseEntityImpl {
private String name;
private Set<TestMany> testManys = new HashSet<TestMany>(0);
public String getName() {
return name;
}
@OneToMany(targetEntity=TestMany.class,
cascade=CascadeType.ALL, fetch=FetchType.EAGER)
@JoinColumn(name="TESTID")
public Set<TestMany> getTestManys() {
return testManys;
}
public void setTestManys(Set<TestMany> testManys) {
this.testManys = testManys;
}
}
Here is the many side.
@SuppressWarnings("serial")
@Entity
@Table(name="TESTMANY")
public class TestMany extends BaseEntityImpl{
private Test test;
private String manyPeople;
@ManyToOne
@JoinColumn(name="TESTID", insertable=false, updatable=false)
public Test getTest() {
return test;
}
@Column(name="MANYPEOPLE")
public String getManyPeople() {
return manyPeople;
}
public void setManyPeople(String manyPeople) {
this.manyPeople = manyPeople;
}
public void setTest(Test test) {
this.test = test;
}
}
Both classes extend the generic base class which doesnt do much but provide an ID.
@MappedSuperclass
public abstract class BaseEntityImpl implements BaseEntity, Serializable {
private static final long serialVersionUID = 7887314289537012320L;
@Id @GeneratedValue(strategy = AUTO)
@Column(name = "ID")
private Long id;
public Long getId() {
return id;
}
@SuppressWarnings("unused")
private void setId(Long id) {
this.id = id;
}
}
Now from the above code the following doesnt work from the Test class:
private Set<TestMany> testManys = new HashSet<TestMany>(0);
@OneToMany(targetEntity=TestMany.class,
cascade=CascadeType.ALL, fetch=FetchType.EAGER)
@JoinColumn(name="TESTID")
public Set<TestMany> getTestManys() {
return testManys;
}
But this does work when placing the annotation above the field:
@OneToMany(targetEntity=TestMany.class,
cascade=CascadeType.ALL, fetch=FetchType.EAGER)
@JoinColumn(name="TESTID")
private Set<TestMany> testManys = new HashSet<TestMany>(0);
And so does this - changing the Set to HashSet and leaving the annotation on the getter:
// here now a HashSet and it works ok, I can place the annotation on the getter.
private HashSet<TestMany> testManys = new HashSet<TestMany>(0);
@OneToMany(targetEntity=TestMany.class,
cascade=CascadeType.ALL, fetch=FetchType.EAGER)
@JoinColumn(name="TESTID")
public Set<TestMany> getTestManys() {
return testManys;
}
The error I get without doing one of the two methods above is:
Stack Trace:
Caused by: org.hibernate.MappingException: Could not determine type for: java.util.Set, at table: TEST, for columns: [org.hibernate.mapping.Column(testManys)]
at org.hibernate.mapping.SimpleValue.getType(SimpleValue.java:306)
at org.hibernate.mapping.SimpleValue.isValid(SimpleValue.java:290)
at org.hibernate.mapping.Property.isValid(Property.java:217)
at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:464)
at org.hibernate.mapping.RootClass.validate(RootClass.java:235)
at org.hibernate.cfg.Configuration.validate(Configuration.java:1335)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1838)
at org.springframework.orm.hibernate3.LocalSessionFactoryBean.newSessionFactory(LocalSessionFactoryBean.java:860)
at org.springframework.orm.hibernate3.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:779)
at org.springframework.orm.hibernate3.AbstractSessionFactoryBean.afterPropertiesSet(AbstractSessionFactoryBean.java:211)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1477)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1417)
... 47 more
My pom:
<properties>
<hibernate.version>3.5.3-Final</hibernate.version>
</properties>
<!-- hibernate dependencies -->
<dependencies>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>3.6.3.Final</version>
</dependency>
<dependency>
<groupId>javassist</groupId>
<artifactId>javassist</artifactId>
<version>3.12.1.GA</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>3.6.3.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-annotations</artifactId>
<version>${hibernate.version}</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-commons-annotations</artifactId>
<version>3.2.0.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate.javax.persistence</groupId>
<artifactId>hibernate-jpa-2.0-api</artifactId>
<version>1.0.1.Final</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-jpamodelgen</artifactId>
<version>1.1.1.Final</version>
</dependency>
</dependencies>
Please can someone explain I think its something very basic I'm missing???
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