I am having a problem with hibernate. I am updating a previously created database created in Oracle SQL in order to get some practice with hibernate. The thing is that I am getting an AnnotationException that one class object is trying to reference something from the other class. Here is the error:
org.hibernate.AnnotationException: #OneToOne or #ManyToOne on com.revature.bank.POJO.BankAccount.customer references an unknown entity: com.revature.bank.POJO.Customer
at org.hibernate.cfg.ToOneFkSecondPass.doSecondPass(ToOneFkSecondPass.java:107)
at org.hibernate.cfg.Configuration.processEndOfQueue(Configuration.java:1580)
at org.hibernate.cfg.Configuration.processFkSecondPassInOrder(Configuration.java:1503)
at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1419)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1856)
at com.revature.bank.POJO.DataFuncImp.createCustomer(DataFuncImp.java:16)
at com.revature.bank.POJO.Main.main(Main.java:9)
So, this is pointing to the line:
SessionFactory sf = new Configuration().configure().buildSessionFactory();
I have read that it might be happening because the annotations but none of the previously asked questions here seemed to work.
Here are my two classes: (i will only put the variables as that's where the error points to):
Customer.java
#Entity
#Table(name="USER_TABLE")
public class Customer {
#Id
#GeneratedValue
private int user_id;
#Column
private String user_fname;
#Column
private String user_lname;
#Column
private String user_email;
#Column
private String user_address;
#Column
private String user_city;
#Column
private String user_state;
#Column
private long cell_num;
#OneToMany(cascade= {CascadeType.ALL}, mappedBy="customer")
#JoinColumn(name="user_id")
private List<BankAccount> bacct;
BankAccount.java
#Entity
#Table(name="USER_ACCOUNT")
public class BankAccount {
#Id
#GeneratedValue
private long acct_id;
#Column
private double balance;
#ManyToOne
#JoinColumn(name="user_id")
private Customer customer;
And here is my hibernate config file as well(edited out the database connection info):
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
<property name="hibernate.connection.url">jdbc:oracle:thin:#localhost:1521:xe</property>
<property name="hibernate.connection.username">adminone</property>
<property name="hibernate.connection.password">adminpass</property>
<property name="hibernate.dialect">org.hibernate.dialect.Oracle11gDialect</property>
<property name="show_sql">true</property>
<property name="hbm2ddl.auto">update</property>
<!-- <property name="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider</property> -->
<!-- <mapping resource="students.hbm.xml"></mapping> -->
<mapping class="com.revature.bank.POJO.Customer"></mapping>
<mapping class="com.revature.bank.POJO.BankAccount"></mapping>
</session-factory>
</hibernate-configuration>
I am using hibernate 3.0. Like i mentioned earlier, i have been trying to figure out the error but none of the online help seemed to fix it. As you can see, I'm not even trying to do anything to the database yet and it is throwing that exception. Any idea on why is this happening? Thank you in advance!!
You shouldn't have JoinColumn on both sides. Just on the owner side, so remove it from the Customer class.
Customer.java:
#OneToMany(cascade= {CascadeType.ALL}, mappedBy="customer")
private List<BankAccount> bacct;
BankAccount.java:
#ManyToOne
#JoinColumn(name="user_id")
private Customer customer;
I have 2 projects:
1 for the entities
1 for a web service
While using Hibernate 4.3.11.Final everything was working properly. I have a hibernate.cfg.xml where I have all the classes so selecting the entities from the DB was ok using Query
Then I changed to Hibernate 5.2.6.Final and I had to change Query for TypedQuery<Entity> and now it complains that the entity is not mapped.
A test I made calls this code.
TypedQuery<Employee> query = getSession().createQuery(
"SELECT e from Employee e where e.username = :username");
query.setParameter("username", employee.getUsername());
return query.getSingleResult();
And it complains that the entity I'm selecting in the query "SELECT e from Employee..." (not the one defined in the TypedQuery) is the one that's not mapped.
Is there a new way to map the entities in 5.2.6? How could I solve this?
The Employee entity:
#Entity
#Table(name = "employee")
#XmlRootElement
public class Employee implements Serializable
{
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Basic(optional = false)
#Column(name = "id")
private Long id;
#Basic(optional = false)
#Column(name = "username")
private String username;
// Getters & Setters...
}
The entry in the hibernate.cfg.xml file is like this:
<hibernate-configuration>
<session-factory>
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.connection.driver_class">com.mysql.cj.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/db</property>
<property name="hibernate.connection.username">user</property>
<property name="hibernate.connection.password">pass</property>
<mapping class="com.entities.Employee"/>
<mapping class="all other entities"/>
If I change the dependency back from 5.2.6.Final to 4.3.11.Final
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>4.3.11.Final</version>
</dependency>
I have no problem and everything works as it should be.
I have entity with two Lists of children entities. When calling EntityManager.find() it returns duplicates based on multiplication of two lists.
I'm using Spring, Jackson and JPA with Hibernate and SQL Server.
When testing with parent that has N elements of first and M of second child entity it always returns N*M elements of both entities.
For example below there are 3 tasks and 5 comments and JPA returns 15 for both lists. (5 copies of task list, and 3 copies of comment list)
Output from controller is:
Comments 15
Tasks 15
And the rest of the code is below.
controller.java
#RequestMapping(method = RequestMethod.GET)
public String listAll(Model model) {
Goal goal = new Goal();
goal = service.getGoalById(25);
System.out.println("Comments " + goal.getComments().size());
System.out.println("Tasks " + goal.getTasks().size());
return "home";
}
service.java
#Transactional
public Goal getGoalById(int goalId) {
Goal goal = em.find(Goal.class, goalId);
return goal;
}
goal.java
#Entity
#Table(name = "goal")
public class Goal {
#Id
#GeneratedValue
private int id;
#JsonManagedReference
#OneToMany(mappedBy = "tasksGoal", cascade = CascadeType.PERSIST, fetch = FetchType.EAGER)
private List<Task> projectTasks = new ArrayList<Task>();
#JsonManagedReference
#OneToMany(mappedBy = "commentsGoal", cascade = CascadeType.PERSIST, fetch = FetchType.EAGER)
private List<Comment> goalComments = new ArrayList<Comment>();
...
}
task.java
#Entity
#Table(name="projectTask")
public class Task {
#Id
#GeneratedValue
private int id;
#JsonBackReference
#ManyToOne (fetch = FetchType.LAZY)
#JoinColumn(name = "task_goal_id")
private Goal tasksGoal;
...
}
comment.java
#Entity
#Table (name="goalComment")
public class Comment {
#Id
#GeneratedValue
private int id;
#JsonBackReference
#ManyToOne (fetch = FetchType.LAZY)
#JoinColumn(name = "goal_id")
private Goal commentsGoal;
...
}
persistence.xml
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.0"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="persistenceUnit"
transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<properties>
<property name="hibernate.dialect" value="org.hibernate.dialect.SQLServer2008Dialect" />
<property name="hibernate.hbm2ddl.auto" value="update" />
<property name="hibernate.ejb.naming_strategy" value="org.hibernate.cfg.ImprovedNamingStrategy" />
<property name="hibernate.connection.charSet" value="UTF-8" />
<!-- Hibernate prints SQL -->
<property name="hibernate.show_sql" value="true" />
</properties>
</persistence-unit>
This is because of your fetch = FetchType.EAGER.
he Hibernate tries to get everything in one shot, i.e. using one single query for each entry of element linked to a "master" object.
Hibernate creates JOINs and tries to get all your collections with one query.
This problem can be successfully solved at a cost of N+1 query, if you add the #Fetch (FetchMode.SELECT) annotation to your collection.
If you really need FetchType.EAGER and don't want to replace your collection with Set you can use #Fetch (FetchMode.SELECT) annotation for your collection:
#JsonManagedReference
#OneToMany(mappedBy = "tasksGoal", cascade = CascadeType.PERSIST, fetch = FetchType.EAGER)
#Fetch (FetchMode.SELECT)
private List projectTasks = new ArrayList();
#JsonManagedReference
#OneToMany(mappedBy = "commentsGoal", cascade = CascadeType.PERSIST, fetch = FetchType.EAGER)
#Fetch (FetchMode.SELECT)
private List<Comment> goalComments = new ArrayList<Comment>();
#Fetch (FetchMode.SELECT)
can help you. it is the default fetching strategy. it enabled the lazy loading of all it’s related collections.
I'm trying to setup JPA with a hibernate implementation for the first time with this test project. Ran into the following error:
Exception in thread "main" javax.persistence.PersistenceException: [PersistenceUnit: ExamModulePu] Unable to build EntityManagerFactory
at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:924)
at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:899)
at org.hibernate.ejb.HibernatePersistence.createEntityManagerFactory(HibernatePersistence.java:59)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:63)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:47)
at service.tests.ExamServiceTest.main(ExamServiceTest.java:18)
Caused by: org.hibernate.AnnotationException: #OneToOne or #ManyToOne on entities.Question.examId references an unknown entity: long
at org.hibernate.cfg.ToOneFkSecondPass.doSecondPass(ToOneFkSecondPass.java:109)
at org.hibernate.cfg.Configuration.processEndOfQueue(Configuration.java:1536)
at org.hibernate.cfg.Configuration.processFkSecondPassInOrder(Configuration.java:1457)
at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1365)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1756)
at org.hibernate.ejb.EntityManagerFactoryImpl.<init>(EntityManagerFactoryImpl.java:96)
at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:914)
These are my entities:
#Entity
public class Exam implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private long id;
private String name;
private int numQuestions;
private int minutesAllotted;
private Date startDate;
private Date endDate;
#OneToMany(mappedBy = "examId", orphanRemoval = true)
private List<Question> questionList;
// Getters and setters here..
}
#Entity
public class Question implements Serializable{
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
private long id;
#ManyToOne
private long examId;
private int points;
private int timeLimit;
private String text;
private String category;
#Embedded
private List<Answer> answerList;
}
#Embeddable
public class Answer implements Serializable {
private int optionNumber;
private String text;
private boolean correct;
}
This is what my persistence.xml looks like:
<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
version="2.0">
<persistence-unit name="ExamModulePu"
transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<class>entities.Exam</class>
<class>entities.Question</class>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/exammoduledb" />
<property name="javax.persistence.jdbc.user" value="root" />
<property name="javax.persistence.jdbc.password" value="root" />
<property name="hibernate.hbm2ddl.auto" value="create" />
</properties>
</persistence-unit>
</persistence>
I haven't created any of the tables, but instead am depending on the hibernate.hb2mddl.auto to do so. But I believe my error springs up even before that happens as it can't generate the persistence unit. Any ideas what I'm doing wrong? I'm making sure I import only javax.persistence.*;
If you look closely at your stacktrace, you will see
Caused by: org.hibernate.AnnotationException: #OneToOne or #ManyToOne on entities.Question.examId references an unknown entity: long
So this field
#ManyToOne
private long examId;
is causing the problem. #ManyToOne has a paramater targetEntity which says:
(Optional) The entity class that is the target of the association.
Defaults to the type of the field or property that stores the association.
Since you haven't provided that parameter, it defaults to long, which is not a managed Entity.
You'll probably want to use
#ManyToOne(targetEntity = Exam.class)
private long examId;
otherwise it won't know what to map to. Or even better
#ManyToOne
private Exam exam;
Just add the class Team to the "hibernate-cfg.xml" file, because Hibernate doesn't identify without adding into it.
FYI, this sometimes happens if you have a hibernate annotation:
#org.hibernate.annotations.Entity
and a JPA annotation:
#javax.persistence.Entity
mixed up
Edit:
Explicitly import the javax annotation.
It took me hours to find the actual issue
I had forgotten the #Entity annotation on the Parent class and the error use to show on the child class.
In my case Hibernate was not able to identify the entity because I had not added that entity in sessionfactory using .addAnnotatedClass(XYZ.class) so it was not able to find that particular entity.
I need help with lazy blob loading in Hibernate.
I have in my web application these servers and frameworks: MySQL, Tomcat, Spring and Hibernate.
The part of database config.
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
<property name="user" value="${jdbc.username}"/>
<property name="password" value="${jdbc.password}"/>
<property name="driverClass" value="${jdbc.driverClassName}"/>
<property name="jdbcUrl" value="${jdbc.url}"/>
<property name="initialPoolSize">
<value>${jdbc.initialPoolSize}</value>
</property>
<property name="minPoolSize">
<value>${jdbc.minPoolSize}</value>
</property>
<property name="maxPoolSize">
<value>${jdbc.maxPoolSize}</value>
</property>
<property name="acquireRetryAttempts">
<value>${jdbc.acquireRetryAttempts}</value>
</property>
<property name="acquireIncrement">
<value>${jdbc.acquireIncrement}</value>
</property>
<property name="idleConnectionTestPeriod">
<value>${jdbc.idleConnectionTestPeriod}</value>
</property>
<property name="maxIdleTime">
<value>${jdbc.maxIdleTime}</value>
</property>
<property name="maxConnectionAge">
<value>${jdbc.maxConnectionAge}</value>
</property>
<property name="preferredTestQuery">
<value>${jdbc.preferredTestQuery}</value>
</property>
<property name="testConnectionOnCheckin">
<value>${jdbc.testConnectionOnCheckin}</value>
</property>
</bean>
<bean id="lobHandler" class="org.springframework.jdbc.support.lob.DefaultLobHandler" />
<bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="configLocation" value="/WEB-INF/hibernate.cfg.xml" />
<property name="configurationClass" value="org.hibernate.cfg.AnnotationConfiguration" />
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">${hibernate.dialect}</prop>
</props>
</property>
<property name="lobHandler" ref="lobHandler" />
</bean>
<tx:annotation-driven transaction-manager="txManager" />
<bean id="txManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory" />
</bean>
The part of entity class
#Lob
#Basic(fetch=FetchType.LAZY)
#Column(name = "BlobField", columnDefinition = "LONGBLOB")
#Type(type = "org.springframework.orm.hibernate3.support.BlobByteArrayType")
private byte[] blobField;
The problem description. I'm trying to display on a web page database records related to files, which was saved in MySQL database. All works fine if a volume of data is small. But the volume of data is big I'm recieving an error java.lang.OutOfMemoryError: Java heap space
I've tried to write in blobFields null values on each row of table. In this case, application works fine, memory doesn't go out of. I have a conclusion that the blob field which is marked as lazy (#Basic(fetch=FetchType.LAZY)) isn't lazy, actually!
I'm confused. Emmanuel Bernard wrote in ANN-418 that #Lob are lazy by default (i.e. you don't even need to use the #Basic(fetch = FetchType.LAZY) annotation).
Some users report that lazy loading of a #Lob doesn't work with all drivers/database.
Some users report that it works when using bytecode instrumentation (javassit? cglib?).
But I can't find any clear reference of all this in the documentation.
At the end, the recommended workaround is to use a "fake" one-to-one mappings instead of properties. Remove the LOB fields from your existing class, create new classes referring to the same table, same primary key, and only the necessary LOB fields as properties. Specify the mappings as one-to-one, fetch="select", lazy="true". So long as your parent object is still in your session, you should get exactly what you want. (just transpose this to annotations).
I would suggest you to use inheritance to handle this scenario. Have a base class without the blob and a derived class containing the byte array. You would use the derived class only when you need to display the blob on the UI.
Of course you could extract that value and put it into a new table with a "#OneToOne" relation that is lazy, however in our application the LOBs are loaded lazily on demand using just this configuration
#Lob
#Fetch(FetchMode.SELECT)
#Type(type="org.hibernate.type.PrimitiveByteArrayBlobType")
byte[] myBlob;
This is tested in our project simultaneously on PostgreSQL, MySQL, SQLServer and Oracle, so it should work for u
Lazy property loading requires buildtime bytecode instrumentation.
Hibernate docs: Using lazy property fetching
If you want to avoid bytecode instrumentation one option is to to create two entities that use same table, one with the blob one without. Then only use the entity with blob when you need the blob.
I had the same issue and this was my fix:
My Entity:
#Entity
#Table(name = "file")
public class FileEntity {
#Id
#GeneratedValue
private UUID id;
#NotNull
private String filename;
#NotNull
#Lob #Basic(fetch = FetchType.LAZY)
private byte[] content;
...
Added plugin to pom.xml:
<plugin>
<groupId>org.hibernate.orm.tooling</groupId>
<artifactId>hibernate-enhance-maven-plugin</artifactId>
<executions>
<execution>
<phase>compile</phase>
<configuration>
<failOnError>true</failOnError>
<enableLazyInitialization>true</enableLazyInitialization>
</configuration>
<goals>
<goal>enhance</goal>
</goals>
</execution>
</executions>
</plugin>
For me lazy load only worked by compiling and then running it, didn't work on eclipse or intellij for example.
I'm using gradle then I did the following to get it working
Annotate entity
Setup Hibernate gradle plugin
build.gradle
buildscript {
repositories {
mavenCentral()
}
dependencies {
classpath "org.hibernate:hibernate-gradle-plugin:5.4.0.Final"
}
}
apply plugin: 'java'
apply plugin: 'application'
apply plugin: 'org.hibernate.orm'
hibernate {
enhance {
enableLazyInitialization = true
enableDirtyTracking = true
enableAssociationManagement = true
}
}
Entity.java
#Entity
public class Person {
#Id
#GeneratedValue
private Integer id;
#Lob
#Basic(fetch = FetchType.LAZY)
#Column(length = 255, nullable = false)
private String name;
Testing
./gradlew run
Full working example
Lazy loading works for me if I use Blob type instead of byte[].
#Column(name = "BlobField", nullable = false)
#Lob
#Basic(fetch = FetchType.LAZY)
private Blob blobField;
This one gets lazily loaded and if you need to retrieve its value access this field:
String value = IOUtils.toByteArray(entity.getBlobField().getBinaryStream());
A simple workarround using #OneTone notation based on the response of #MohammadReza Alagheband (Why does #Basic(fetch=lazy) doesn't work in my case?) but without the requirement of create a new table for each required lazy attribute is the following:
#Getter
#Setter
#Entity
#Table(name = "document")
#AllArgsConstructor
#NoArgsConstructor
public class DocumentBody implements java.io.Serializable{
#Column(name = "id", insertable = false)
#ReadOnlyProperty
#Id
#PrimaryKeyJoinColumn
private Integer id;
#Column(name = "body", unique = true, nullable = false, length = 254)
#JsonView({JSONViews.Simple.class, JSONViews.Complete.class})
private String content;
}
#Getter
#Entity
#Setter
#Table(name = "document")
#AllArgsConstructor
#NoArgsConstructor
public class DocumentTitle implements java.io.Serializable{
#Column(name = "id", insertable = false)
#ReadOnlyProperty
#Id
private Integer id;
#Column(name = "title", unique = true, nullable = false, length = 254)
#JsonView({JSONViews.Simple.class, JSONViews.Complete.class})
private String content;
}
public class Document implements java.io.Serializable {
#Id
#GeneratedValue(strategy = IDENTITY)
#Column(name = "id", unique = true, nullable = false)
#JsonView({JSONViews.Simple.class, JSONViews.Complete.class})
private Integer id;
//Also it is posssible to prove with #ManyToOne
#OneToOne(fetch = FetchType.LAZY, optional = false, cascade = {CascadeType.MERGE, CascadeType.PERSIST, CascadeType.REFRESH})
#JoinColumn(name = "id", referencedColumnName = "id", nullable = false)
#JsonView({JSONViews.Simple.class, JSONViews.Complete.class})
private DocumentTitle title;
#OneToOne(fetch = FetchType.LAZY, optional = false, cascade = {CascadeType.MERGE, CascadeType.PERSIST, CascadeType.REFRESH})
#JoinColumn(name = "id", referencedColumnName = "id", nullable = false)
#JsonView({JSONViews.Simple.class, JSONViews.Complete.class})
private DocumentBody body;
}