org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set

First remove all of your configuration Spring Boot will start it for you.

Make sure you have an application.properties in your classpath and add the following properties.

spring.datasource.url=jdbc:postgresql://localhost:5432/teste?charSet=LATIN1
spring.datasource.username=klebermo
spring.datasource.password=123

spring.jpa.database-platform=org.hibernate.dialect.PostgreSQLDialect
spring.jpa.show-sql=false
spring.jpa.hibernate.ddl-auto=create

If you really need access to a SessionFactory and that is basically for the same datasource, then you can do the following (which is also documented here although for XML, not JavaConfig).

@Configuration        
public class HibernateConfig {

    @Bean
    public HibernateJpaSessionFactoryBean sessionFactory(EntityManagerFactory emf) {
         HibernateJpaSessionFactoryBean factory = new HibernateJpaSessionFactoryBean();
         factory.setEntityManagerFactory(emf);
         return factory;
    }
}

That way you have both an EntityManagerFactory and a SessionFactory.

UPDATE: As of Hibernate 5 the SessionFactory actually extends the EntityManagerFactory. So to obtain a SessionFactory you can simply cast the EntityManagerFactory to it or use the unwrap method to get one.

public class SomeHibernateRepository {

  @PersistenceUnit
  private EntityManagerFactory emf;

  protected SessionFactory getSessionFactory() {
    return emf.unwrap(SessionFactory.class);
  }

}

Assuming you have a class with a main method with @EnableAutoConfiguration you don't need the @EnableTransactionManagement annotation, as that will be enabled by Spring Boot for you. A basic application class in the com.spring.app package should be enough.

@Configuration
@EnableAutoConfiguration
@ComponentScan
public class Application {


    public static void main(String[] args) throws Exception {
        SpringApplication.run(Application.class, args);
    }

} 

Something like that should be enough to have all your classes (including entities and Spring Data based repositories) detected.

UPDATE: These annotations can be replaced with a single @SpringBootApplication in more recent versions of Spring Boot.

@SpringBootApplication
public class Application {

    public static void main(String[] args) throws Exception {
        SpringApplication.run(Application.class, args);
    }
} 

I would also suggest removing the commons-dbcp dependency as that would allow Spring Boot to configure the faster and more robust HikariCP implementation.

I was facing a similar problem when starting up the application (using Spring Boot) with the database server down.

Hibernate can determine the correct dialect to use automatically, but in order to do this, it needs a live connection to the database.

add spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQLDialect in application.properties file