Migration from ObjectDB to MySQL in Spring

I've been using objectDB as a database in my Spring application, yet it is only free for up to 10 tables, so i've tried to migrate to MySQL. When I look into database the tables are created, but when I try to persist I get the NullPointerException. Here are my configuration files:

persistence.xml:

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://ift.tt/UICAJV" xmlns:xsi="http://ift.tt/ra1lAU" xsi:schemaLocation="http://ift.tt/UICAJV   http://ift.tt/O9YdEP">
  <persistence-unit name="cinemabookPU" transaction-type="JTA">
    <provider>org.hibernate.ejb.HibernatePersistence</provider>
    <jta-data-source>cinemaDbCon</jta-data-source>
    <exclude-unlisted-classes>false</exclude-unlisted-classes>
    <properties>
      <property name="hibernate.transaction.jta.platform" value="org.hibernate.service.jta.platform.internal.SunOneJtaPlatform" />
      <property name="hibernate.hbm2ddl.auto" value="update" /> 
    </properties>
  </persistence-unit>
</persistence>

spring-servlet.xml:

<?xml version="1.0" encoding="windows-1252"?>
<beans xmlns="http://ift.tt/GArMu6"
       xmlns:xsi="http://ift.tt/ra1lAU"
       xmlns:p="http://ift.tt/1jdM0fE"
       xmlns:context="http://ift.tt/GArMu7"
       xmlns:mvc="http://ift.tt/1bHqwjR"
       xmlns:aop="http://ift.tt/OpNdV1"
       xmlns:tx="http://ift.tt/OGfeU2"
       xsi:schemaLocation="
       http://ift.tt/GArMu6
       http://ift.tt/QEDs1e
       http://ift.tt/GArMu7
       http://ift.tt/QEDs1k
       http://ift.tt/1bHqwjR
       http://ift.tt/1bVJL9q
       http://ift.tt/OpNdV1
       http://ift.tt/QEDs1g
       http://ift.tt/OGfeU2
       http://ift.tt/1cQrvTl">

    <!-- Use @Component annotations for bean definitions -->

    <context:component-scan base-package="cinema"/>

    <!-- Use @Controller annotations for MVC controller definitions -->

    <mvc:resources mapping="/resources/**" location="/resources/" />

    <mvc:annotation-driven />

    <bean id="emf" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="loadTimeWeaver">
            <bean class="org.springframework.instrument.classloading.glassfish.GlassFishLoadTimeWeaver"/>
        </property>
    </bean>

    <tx:jta-transaction-manager />

    <tx:annotation-driven />

    <bean class=
     "org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/"/>
    </bean>

    <bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />

    <import resource="/spring-security.xml" />
</beans>

Model City:

package cinema.model;


import java.io.Serializable;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;


@Entity
public class City implements Serializable {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Long id;
    private String name;

    protected City() {

    }

    public City(Long id, String name) {
        this.id = id;
        this.name = name;
    }

    public City(String name) {
            this.name = name;       
    }


    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }    


    @Override
    public String toString() {
            return name;
    }
}

CityService.java:

package cinema.services;

import cinema.model.City;
import java.util.List;
import org.springframework.transaction.annotation.Transactional;


public interface CityService {

    // Stores a new city:
    @Transactional
    public void persist(City city);

    // Retrieves all the citys:
    public List<City> getAllCities();

    public City getCityById(Long id);

    public void deleteAllCities();
}

CityServiceImpl.java:

package cinema.services.impl;


import cinema.services.CityService;
import cinema.model.City;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.TypedQuery;
import org.springframework.stereotype.Component;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;


@Component
public class CityServiceImpl implements CityService {
    // Injected database connection:
    @PersistenceContext(unitName="cinemabookPU")
    private EntityManager em;

    public EntityManager getEm() {
        return em;
    }

    public void setEm(EntityManager em) {
        this.em = em;
    }


    // Stores a new city:
    @Transactional
    public void persist(City city) {
        em = getEm();
        System.out.println("EM "+em);
        em.persist(city);
    }

    // Retrieves all the citys:
    public List<City> getAllCities() {
        TypedQuery<City> query = em.createQuery(
            "SELECT c FROM City c", City.class);
        return query.getResultList();
    }

    public City getCityById(Long id) {
        TypedQuery<City> query = em.createQuery(
                "SELECT c FROM City c WHERE c.id = :id", City.class);
        return query.setParameter("id", id).getSingleResult();
    }

    @Transactional(propagation = Propagation.REQUIRED)
    public void deleteAllCities() {
        TypedQuery<City> query = em.createQuery(
            "DELETE FROM City", City.class);
        query.executeUpdate();
    }
}

Any help will be greatly appreciated.