Erro na conexão com o banco postgresql

java.lang.UnsupportedOperationException: The application must supply JDBC connections.

// Codigo

        <dependency></br>
            <groupId>org.postgresql</groupId></br>
            <artifactId>postgresql</artifactId></br>
            <version>9.3-1100-jdbc4</version>
        </dependency>

package br.com.melhorcaminho.config;

import java.util.Properties;

import javax.persistence.EntityManagerFactory;

import org.springframework.context.annotation.Bean;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.JpaVendorAdapter;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.annotation.EnableTransactionManagement;

@EnableTransactionManagement
public class JpaConfigurationApp {

    @Bean
    public LocalContainerEntityManagerFactoryBean entityManager(){
        LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
        JpaVendorAdapter jpaAdapter= new HibernateJpaVendorAdapter();

        factory.setJpaVendorAdapter(jpaAdapter);

        DriverManagerDataSource source = new DriverManagerDataSource();
        source.setUsername("postgres");
        source.setPassword("");
        source.setUrl("jdbc:postgresql://localhost:5432/MC");
        source.setDriverClassName("org.postgresql.Driver");

        Properties props = new Properties();
        props.setProperty("hibernate.dialect" , "org.hibernate.dialect.PostgreSQLDialect");
        props.setProperty("hibernate.show_sql", "true");
        props.setProperty("hibernate.hbm2ddl.auto", "update");

        factory.setJpaProperties(props);

        factory.setPackagesToScan("br.com.melhorcaminho.model");
        return factory;
    }
    @Bean
    public JpaTransactionManager jpaTransactionManager(EntityManagerFactory factory){
        return new JpaTransactionManager(factory);
    }

}

Como corrigir esse erro ?