Error in bean creation
<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>