title: Error in bean creation
body: <p>I am trying to configure Hibernate, Spring Data JPA for MySQL. I would really appreciate if anyone could point out what I am missing? Also, I was unable to find the reason for IllegalArgumentException.</p>
  
  <pre><code>    2016-07-05 19:07:06.677  INFO 7760 --- [           main] o.s.j.d.DriverManagerDataSource          : Loaded JDBC driver: com.mysql.jdbc.Driver
      file:/C:/Users/eprisur/.gradle/caches/modules-2/files-2.1/org.hibernate.javax.persistence/hibernate-jpa-2.1-api/1.0.0.Final/5e731d961297e5a07290bfaf3db1fbc8bbbf405a/hibernate-jpa-2.1-api-1.0.0.Final.jar
      2016-07-05 19:07:06.799  WARN 7760 --- [           main] ationConfigEmbeddedWebApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [com/test/authflow/config/DatabaseConfig.class]: Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Class name must not be null
      2016-07-05 19:07:06.810  INFO 7760 --- [           main] o.apache.catalina.core.StandardService   : Stopping service Tomcat
      2016-07-05 19:07:06.822 ERROR 7760 --- [           main] o.s.boot.SpringApplication               : Application startup failed
  
      org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [com/test/authflow/config/DatabaseConfig.class]: Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Class name must not be null
          at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1578) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
          at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
          at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
          at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
          at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
          at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
          at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
          at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1054) ~[spring-context-4.2.5.RELEASE.jar:4.2.5.RELEASE]
          at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:829) ~[spring-context-4.2.5.RELEASE.jar:4.2.5.RELEASE]
          at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:538) ~[spring-context-4.2.5.RELEASE.jar:4.2.5.RELEASE]
          at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118) ~[spring-boot-1.3.3.RELEASE.jar:1.3.3.RELEASE]
          at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:766) [spring-boot-1.3.3.RELEASE.jar:1.3.3.RELEASE]
          at org.springframework.boot.SpringApplication.createAndRefreshContext(SpringApplication.java:361) [spring-boot-1.3.3.RELEASE.jar:1.3.3.RELEASE]
          at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) [spring-boot-1.3.3.RELEASE.jar:1.3.3.RELEASE]
          at org.springframework.boot.SpringApplication.run(SpringApplication.java:1191) [spring-boot-1.3.3.RELEASE.jar:1.3.3.RELEASE]
          at org.springframework.boot.SpringApplication.run(SpringApplication.java:1180) [spring-boot-1.3.3.RELEASE.jar:1.3.3.RELEASE]
          at com.test.authflow.LoginSystemApplication.main(LoginSystemApplication.java:11) [bin/:na]
      Caused by: java.lang.IllegalArgumentException: Class name must not be null
          at org.springframework.util.Assert.notNull(Assert.java:115) ~[spring-core-4.2.5.RELEASE.jar:4.2.5.RELEASE]
          at org.springframework.util.ClassUtils.convertClassNameToResourcePath(ClassUtils.java:960) ~[spring-core-4.2.5.RELEASE.jar:4.2.5.RELEASE]
          at org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager.buildDefaultPersistenceUnitInfo(DefaultPersistenceUnitManager.java:522) ~[spring-orm-4.2.5.RELEASE.jar:4.2.5.RELEASE]
          at org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager.readPersistenceUnitInfos(DefaultPersistenceUnitManager.java:503) ~[spring-orm-4.2.5.RELEASE.jar:4.2.5.RELEASE]
          at org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager.preparePersistenceUnitInfos(DefaultPersistenceUnitManager.java:440) ~[spring-orm-4.2.5.RELEASE.jar:4.2.5.RELEASE]
          at org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager.afterPropertiesSet(DefaultPersistenceUnitManager.java:424) ~[spring-orm-4.2.5.RELEASE.jar:4.2.5.RELEASE]
          at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:310) ~[spring-orm-4.2.5.RELEASE.jar:4.2.5.RELEASE]
          at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:319) ~[spring-orm-4.2.5.RELEASE.jar:4.2.5.RELEASE]
          at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1637) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
          at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1574) ~[spring-beans-4.2.5.RELEASE.jar:4.2.5.RELEASE]
  
  
    2016-07-05 19:07:06.825  WARN 7760 --- [           main] o.s.boot.SpringApplication               : Error handling failed (Error creating bean with name 'delegatingApplicationListener' defined in class path resource [org/springframework/security/config/annotation/web/configuration/WebSecurityConfiguration.class]: BeanPostProcessor before instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.transaction.annotation.ProxyTransactionManagementConfiguration': Initialization of bean failed; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'org.springframework.context.annotation.ConfigurationClassPostProcessor.importRegistry' is defined)
  </code></pre>
  
  <p>My build.gradle looks like:</p>
  
  <pre><code>  buildscript {
       ext { springBootVersion = '1.3.3.RELEASE' }
          repositories {
                mavenCentral()
                     maven { url "https://repo.spring.io/snapshot" }
                     maven { url "https://repo.spring.io/milestone" }
                       }
         dependencies {
                classpath("org.springframework.boot:spring-boot-gradle plugin:${springBootVersion}")      
  
              }
                }
  
  apply plugin: 'java'            
  apply plugin: 'eclipse-wtp'         
  apply plugin: 'spring-boot'         
  
  
      jar {
        manifest {
          attributes 'Main-Class': 'com.test.authflow.LoginSystemApplication' 
                 }
         }
  
           sourceCompatibility = 1.8          
           targetCompatibility = 1.8
  
           repositories {
            mavenCentral()
               maven { url "https://repo.spring.io/snapshot" }
               maven { url "https://repo.spring.io/milestone" }
                          }
  
            configurations {
                    providedRuntime
  
                      }
  
           configurations {
                 runtime.exclude group: "org.slf4j", module: "slf4j-simple"
                 compile.exclude group: "org.slf4j", module: "slf4j-simple"
  
                          }
  
           dependencies {
  
                    //for external container  
           providedRuntime("org.springframework.boot:spring-boot-starter-tomcat")
            providedRuntime("org.apache.tomcat:tomcat-juli")
            providedRuntime("org.apache.tomcat:tomcat-jdbc")
  
  
  
              }
  
             ext['hibernate.version'] = '5.2.1.Final'
  
         dependencies {
             compile ('org.springframework.boot:spring-boot-starter')
             compile("org.springframework.boot:spring-boot-starter-web")
             compile("org.springframework.boot:spring-boot-starter-data-jpa")
             compile("org.springframework.boot:spring-boot-starter-security")
             compile("mysql:mysql-connector-java")
                     }
              task wrapper(type: Wrapper) {
                gradleVersion = '2.13'
                }
  </code></pre>
  
  <p>This is my DatabaseConfig class:</p>
  
  <pre><code>package com.test.authflow.config;
  
  
  import java.util.Properties;
  import javax.persistence.EntityManager;
  import javax.persistence.EntityManagerFactory;
  import javax.sql.DataSource;
  
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.context.annotation.Bean;
  import org.springframework.context.annotation.Configuration;
  import org.springframework.context.annotation.PropertySource;
  import org.springframework.core.env.Environment;
  import org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor;
  import org.springframework.jdbc.datasource.DriverManagerDataSource;
  import org.springframework.orm.jpa.JpaTransactionManager;
  import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
  import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
  import org.springframework.transaction.PlatformTransactionManager;
  import org.springframework.transaction.annotation.EnableTransactionManagement;
  
  
  
  @Configuration
  @PropertySource(value = { "application.properties" })
  @EnableTransactionManagement
  public class DatabaseConfig {
  
  @Bean
  public DataSource dataSource()
  {
      DriverManagerDataSource dataSource = new DriverManagerDataSource();
      dataSource.setDriverClassName(env.getProperty("db.driver"));
      dataSource.setUrl(env.getProperty("db.url"));
      dataSource.setUsername(env.getProperty("db.username"));
      dataSource.setPassword(env.getProperty("db.password"));
      return dataSource;
  }
  
  
  
  
  @Bean
  public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
      LocalContainerEntityManagerFactoryBean em = 
              new LocalContainerEntityManagerFactoryBean();
  
      em.setDataSource(dataSource());
  
      // Classpath scanning of @Component, @Service, etc annotated class
      em.setPackagesToScan(
              env.getProperty("em.setPackagesToScan"));
  
      //Vendor Adapter
      HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
      em.setJpaVendorAdapter(vendorAdapter);
  
      //Hibernate Properties
      Properties additionalProperties = new Properties();
      additionalProperties.put(
              "hibernate.dialect",
              env.getProperty("hibernate.dialect"));
      additionalProperties.put(
              "hibernate.show_sql",
              env.getProperty("hibernate.dialect"));
      additionalProperties.put(
              "hibernate.hbm2ddl.auto",
              env.getProperty("hibernate.hbm2ddl.auto"));
      em.setJpaProperties(additionalProperties);
  
      System.out.println(EntityManager.class.getProtectionDomain()
              .getCodeSource()
              .getLocation());
  
      return em;
  } 
  
  
  @Bean
  public PlatformTransactionManager transactionManager(EntityManagerFactory emf) {
      JpaTransactionManager transactionManager =
              new JpaTransactionManager();
      transactionManager.setEntityManagerFactory(emf);
      return transactionManager;
  
  }
  
  
  public PersistenceExceptionTranslationPostProcessor ExceptionTranslation() {
      return new PersistenceExceptionTranslationPostProcessor();
  }
  
  
  
  @Autowired
  private Environment env;
  
  
  }
  </code></pre>