minor fix for spring config

Author: eugenp

spring-jpa/src/main/java/org/baeldung/spring/PersistenceJPAConfig.java

@@ -2,6 +2,7 @@
 
 import java.util.Properties;
 
+import javax.persistence.EntityManagerFactory;
 import javax.sql.DataSource;
 
 import org.springframework.beans.factory.annotation.Autowired;
@@ -58,10 +59,9 @@ public DataSource dataSource() {
     }
 
     @Bean
-    public PlatformTransactionManager transactionManager() {
+    public PlatformTransactionManager transactionManager(final EntityManagerFactory emf) {
         final JpaTransactionManager transactionManager = new JpaTransactionManager();
-        transactionManager.setEntityManagerFactory(entityManagerFactoryBean().getObject());
-
+        transactionManager.setEntityManagerFactory(emf);
         return transactionManager;
     }