i have created a maven project and added **Spring4, Hibernate4** libs through pom.xml
I m trying to link my web app with my database created in **PostgreSql**, but when i publish my project in **apache tomcat 7** the following exception occurs : 

> 
> org.springframework.beans.factory.BeanCreationException: Error
>  creating bean with name 'emf' defined in ServletContext resource
>  [/WEB-INF/applicationContext.xml]: Invocation of init method failed;
>  nested exception is java.lang.IllegalArgumentException: No
>  PersistenceProvider specified in EntityManagerFactory configuration,
>  and chosen PersistenceUnitInfo does not specify a provider class name
>  either at
>  org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1553)
>  at
>  org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:539)
>  at
>  org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
>  at
>  org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304)
>  at
>  org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
>  at
>  org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
>  at
>  org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
>  at
>  org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:973)
>  at
>  org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:750)
>  at
>  org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482)
>  at
>  org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:403)
>  at
>  org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:306)
>  at
>  org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106)
>  at
>  org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4994)
>  at
>  org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5492)
>  at
>  org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
>  at
>  org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1575)
>  at
>  org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1565)
>  at java.util.concurrent.FutureTask.run(Unknown Source) at
>  java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at
>  java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at
>  java.lang.Thread.run(Unknown Source) Caused by:
>  java.lang.IllegalArgumentException: No PersistenceProvider specified
>  in EntityManagerFactory configuration, and chosen PersistenceUnitInfo
>  does not specify a provider class name either at
>  org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:318)
>  at
>  org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:318)
>  at
>  org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1612)
>  at
>  org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1549)
>  ... 21 more
> 
> 
> 

here is my applicationContext.xml:

```
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:jdbc="http://www.springframework.org/schema/jdbc"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-4.0.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-4.0.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd">

    <context:component-scan base-package="com.medsoft.stadto">
        <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
    </context:component-scan>

    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="org.postgresql.Driver" />
        <property name="url" value="jdbc:postgresql://localhost:1993/Posts" />
        <property name="username" value="postgres" />
        <property name="password" value="123" />
    </bean>

    <bean class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean" id="emf">
        <property name="packagesToScan" value="com.medsoft.stadto.entity" />
        <property name="dataSource" ref="dataSource" />
        <property name="jpaProperties">
            <props>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.hbm2dll.auto">create</prop>
            </props>
        </property>
    </bean>

    <tx:annotation-driven transaction-manager="txManager" />
    <bean id="txManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="dataSource" ref="dataSource" />
    </bean>

</beans>

```