i have a exception when i try to fetch from the database.
I have three entities with a ManyToOne relation. One A -> Many B, One A -> C and One B -> Many D. I use the EAGER'Type. but i get exception. See below.
The first entity:
@Entity
@Table
public class A {
@Id
@Column(columnDefinition = "VARCHAR(50)", nullable = false)
private String aId;
@OneToMany(mappedBy = "a", targetEntity = B.class, fetch = FetchType.EAGER, cascade = CascadeType.ALL)
private List<B> b;
@OneToMany(mappedBy = "a", targetEntity = C.class, cascade = CascadeType.ALL)
private List<C> c;
The second one:
@Entity
@Table
public class B {
@Id
@Column(columnDefinition = "VARCHAR(50)", nullable = false)
private String bId;
@ManyToOne(targetEntity = A.class, cascade = CascadeType.ALL)
@JoinColumn(name = "aId", referencedColumnName = "aId")
private A a;
@OneToMany(mappedBy = "b", targetEntity = D.class, fetch = FetchType.EAGER, cascade = CascadeType.ALL)
private List<D> d;
The last one:
@Entity
@Table
public class D {
@Id
@Column(columnDefinition = "VARCHAR(50)", nullable = false)
private String dId;
@ManyToOne(targetEntity = B.class, cascade = CascadeType.ALL)
@JoinColumn(name = "bId", referencedColumnName = "bId",)
private B b;
when i run the query, i got this execption:
Invocation of init method failed; nested exception is org.hibernate.loader.MultipleBagFetchException: cannot simultaneously fetch multiple bags
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1566)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:539)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:303)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:299)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:956)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:747)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
at org.springframework.context.annotation.AnnotationConfigApplicationContext.<init>(AnnotationConfigApplicationContext.java:84)
at de.emo.cit.tuberlin.GetController.getUDDISLA(GetController.java:44)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
when i change the fetch'type to LAZY, i get this execption:
Caused by: org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: B.d, could not initialize proxy - no Session
Any idea? Thanks ;-)
