1

When i autowire SessionFactory it works fine, but as i open my session using

Session session = sessionFactory.openSession()

it gives the following error 

SEVERE: Exception sending context initialized event to listener instance of class [org.springframework.web.context.ContextLoaderListener]
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'adminController': Unsatisfied dependency expressed through field 'categoryService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'categoryService': Unsatisfied dependency expressed through field 'categoryDao'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'categoryDao' defined in file [D:\eclipse-workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\exuberancesolutions\WEB-INF\classes\com\exuberancesolutions\daoImpl\CategoryDaoImpl.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.exuberancesolutions.daoImpl.CategoryDaoImpl]: Constructor threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:643)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:130)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1422)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517)
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:879)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:878)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:401)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:292)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:103)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:5134)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5662)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
    at org.apache.catalina.core.StandardContext.reload(StandardContext.java:4153)
    at org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:446)
    at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1461)
    at org.apache.catalina.core.StandardContext.backgroundProcess(StandardContext.java:6004)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1660)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1670)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1670)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1638)
    at java.base/java.lang.Thread.run(Thread.java:844)
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'categoryService': Unsatisfied dependency expressed through field 'categoryDao'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'categoryDao' defined in file [D:\eclipse-workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\exuberancesolutions\WEB-INF\classes\com\exuberancesolutions\daoImpl\CategoryDaoImpl.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.exuberancesolutions.daoImpl.CategoryDaoImpl]: Constructor threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:643)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:130)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1422)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517)
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1287)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1207)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:640)
    ... 27 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'categoryDao' defined in file [D:\eclipse-workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\exuberancesolutions\WEB-INF\classes\com\exuberancesolutions\daoImpl\CategoryDaoImpl.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.exuberancesolutions.daoImpl.CategoryDaoImpl]: Constructor threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1320)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1214)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:557)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517)
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1287)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1207)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:640)
    ... 40 more
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.exuberancesolutions.daoImpl.CategoryDaoImpl]: Constructor threw exception; nested exception is java.lang.NullPointerException
    at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:216)
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:87)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1312)
    ... 51 more
Caused by: java.lang.NullPointerException
    at com.exuberancesolutions.daoImpl.CategoryDaoImpl.<init>(CategoryDaoImpl.java:19)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:488)
    at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:203)
    ... 53 more

HibernateConfig.java

package com.exuberancesolutions.config;

import java.util.Properties;

import javax.sql.DataSource;

import org.apache.tomcat.dbcp.dbcp.BasicDataSource;
import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.orm.hibernate5.HibernateTransactionManager;
import org.springframework.orm.hibernate5.LocalSessionFactoryBuilder;
import org.springframework.transaction.annotation.EnableTransactionManagement;



@Configuration
@ComponentScan("com.exuberancesolutions.entity")
@EnableTransactionManagement
public class HibernateConfig {
    private final static String DATABASE_URL = "jdbc:mysql://127.0.0.1:3306/rajeev?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC";
    private final static String DATABASE_DRIVER = "com.mysql.jdbc.Driver";
    private final static String DATABASE_DAILECT = "org.hibernate.dialect.MySQL57Dialect";
    private final static String DATABASE_USERNAME = "root";
    private final static String DATABASE_PASSWORD = "";

    @Bean
    public DataSource getDataSource() {
        BasicDataSource dataSource = new BasicDataSource();
        dataSource.setDriverClassName(DATABASE_DRIVER);
        dataSource.setUrl(DATABASE_URL);
        dataSource.setUsername(DATABASE_USERNAME);
        dataSource.setPassword(DATABASE_PASSWORD);
        return dataSource;
    }

    @Bean
    @Autowired
    public SessionFactory getSessionFactory(DataSource dataSource) {
        LocalSessionFactoryBuilder builder = new LocalSessionFactoryBuilder(dataSource);
        builder.addProperties(getHibernateProperties());
        builder.scanPackages("com.exuberancesolutions.entity");
        return builder.buildSessionFactory();
    }

    private Properties getHibernateProperties() {
        Properties properties = new Properties();
        properties.put("hibernate.dialect",DATABASE_DAILECT);
        properties.put("hibernate.show.sql","true");
        properties.put("hibernate.hbm2ddl.auto","create");
        return properties;
    }
    @Bean
    @Autowired
    public HibernateTransactionManager getTransactionManager(SessionFactory sessionFactory) {
        HibernateTransactionManager tm = new HibernateTransactionManager(sessionFactory);
        return tm;
    }
}

DaoImpl.java

package com.exuberancesolutions.daoImpl;




import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;

import com.exuberancesolutions.dao.CategoryDao;
import com.exuberancesolutions.entity.Category;

@Repository("categoryDao")
public class CategoryDaoImpl implements CategoryDao {
    @Autowired
    SessionFactory sessionFactory;
    Session session = sessionFactory.openSession();
    Transaction tx = null;
    @Override
    public boolean save(Category category) {
        // TODO Auto-generated method stub if inserted return true, other false
        return false;
    }

}

If you need any other code please let me know, i have checked my versions the seems good.

i tryed using xml it worked fine, but can find whats wrong in this code. i'm stuck in middle of no where, a help would be appreciated.

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1 Answer 1

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1

This is the issue:

@Autowired
SessionFactory sessionFactory;
Session session = sessionFactory.openSession(); //Issue is here

You are trying to get a session, when sessionFactory is not available yet, as the sessionFactory is only Autowired after the categoryDao has been constructed.

Do this:

@Autowired
SessionFactory sessionFactory;
Session session;

@PostConstruct
public void init() {
    session = sessionFactory.openSession();
}

In short, it's all about order of construction.

Note: Constructor injection would have worked too, and you wouldn't need the @PostConstruct.

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4 Comments

Thank you so much for the answer, it worked for me. Can you explain what was wring before, i'm new to this spring mvc, and do i have to write the @PostContruct in each of my DaoImpl class, and is there a way i can do the same once in config file.
Okay I get it the sessionfactory will get Autowired after the construction of categoryDao, but before it get constructed m calling the openSession(), if I try to do it inside a method, i.e inside my 'public boolean save()' method them it will work ?Relieved that my syntax and logic was correct it was mainly about the order of instantiating the class and calling the method.
Right, but normally if you are using Spring Boot you don't even need to manipulate the session factory. You create your class as an interface that extends CrudRepository<T,ID> or JpaRepository<T,ID>, Spring will do its magic and you have the save method available out of the box.
m creating a web application so i started with Spring web. MVC architecture.

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