LazyInitializationException for some of requests - spring

Question

This is probably a duplicate, but I am struggling with this problem for few days now. After dozens of tutorials, books, stack answers etc I am in the dead end.
This is RESTfull Spring hibernate app
How to eliminate lazyinitializationexception and problems with Session? I tried to set eager fetch in model class, but it didn't work for me, I have Transaction annotations but its still the same. I bet that it must be set somehow in Spring xml config, but have no clue how to do that.
Why ... /getAllCountries works perfectly fine, and /getCountry/id throw Session error? I see no difference between them.
Please give me a code based answer.
Controller:
#RestController
public class CountryController {
#Autowired
CountryService countryService;
#RequestMapping(value = "/getAllCountries", method = RequestMethod.GET, headers = "Accept=application/json")
public List<Country> getCountries() {
List<Country> listOfCountries = countryService.getAllCountries();
return listOfCountries;
}
#RequestMapping(value = "/getCountry/{id}", method = RequestMethod.GET, headers = "Accept=application/json")
public Country getCountryById(#PathVariable int id) {
return countryService.getCountry(id);
}
// .....
}
DAO:
#Repository
public class CountryDAO {
#Autowired
private SessionFactory sessionFactory;
public void setSessionFactory(SessionFactory sf) {
this.sessionFactory = sf;
}
public List<Country> getAllCountries() {
Session session = this.sessionFactory.getCurrentSession();
List<Country> countryList = session.createQuery("from Country").list();
return countryList;
}
public Country getCountry(int id) {
Session session = this.sessionFactory.getCurrentSession();
Country country = (Country) session.load(Country.class, new Integer(id));
return country;
}
// ......
}
Service:
#Service("countryService")
public class CountryService {
#Autowired
CountryDAO countryDao;
#Transactional
public List<Country> getAllCountries() {
return countryDao.getAllCountries();
}
#Transactional
public Country getCountry(int id) {
return countryDao.getCountry(id);
}
}
Entity:
#Entity
#Table(name="COUNTRY")
public class Country{
#Id
#Column(name="id")
#GeneratedValue(strategy=GenerationType.IDENTITY)
int id;
#Column(name="countryName")
String countryName;
#Column(name="population")
long population;
public Country() {
super();
}
public Country(int i, String countryName,long population) {
super();
this.id = i;
this.countryName = countryName;
this.population=population;
}
// getters and setters...
}
Spring config xml:
<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns="http://www.springframework.org/schema/mvc"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:beans="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">
<annotation-driven />
<resources mapping="/resources/**" location="/resources/" />
<beans:bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
destroy-method="close">
<beans:property name="driverClassName" value="org.postgresql.Driver" />
<beans:property name="url"
value="..." />
<beans:property name="username" value="postgres" />
<beans:property name="password" value="..." />
</beans:bean>
<!-- Hibernate 4 SessionFactory Bean definition -->
<beans:bean id="hibernate4AnnotatedSessionFactory"
class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<beans:property name="dataSource" ref="dataSource" />
<beans:property name="annotatedClasses">
<beans:list>
<beans:value>org.arpit.java2blog.model.Country</beans:value>
</beans:list>
</beans:property>
<beans:property name="hibernateProperties">
<beans:props>
<beans:prop key="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect
</beans:prop>
<beans:prop key="hibernate.show_sql">true</beans:prop>
</beans:props>
</beans:property>
</beans:bean>
<context:component-scan base-package="org.arpit.java2blog" />
<tx:annotation-driven transaction-manager="transactionManager"/>
<beans:bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
<beans:property name="sessionFactory" ref="hibernate4AnnotatedSessionFactory" />
</beans:bean>
</beans:beans>
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
version="3.0">
<display-name>Archetype Created Web Application</display-name>
<servlet>
<servlet-name>spring</servlet-name>
<servlet-class>
org.springframework.web.servlet.DispatcherServlet
</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>spring</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>

Answer 1

Your problem comes from the Session.load() method that doesn't return an object but a proxy of the object which is initialized at the first access of an non-identifier property.
Hibernate Documentation:
T load(Class theClass,
Serializable id)
Return the persistent instance of the given entity class with the given identifier, assuming that the
instance exists. This method might return a proxied instance that is
initialized on-demand, when a non-identifier method is accessed.
And for you it means it's initialized when Spring will try to marshall the object, which is when the Session is close.
To fix it you can either add #org.hibernate.annotations.Proxy(lazy = false) on the class level, use Session.get() instead of Session.load() in the dao to get a fully loaded object (depending on the lazy strategy on members).
Or manually trigger the lazy loading when the Session is still like by calling any member of the object (like calling List.size() on a collection to force the loading).