在同一方法上使用@Transactional和@PostConstruct

Question

我尝试使用下面的代码初始化数据库

@Component
public class DataBase {
   @Transactional
   @PostConstruct
   public void init() {
       Query nativeQuery = entityManager.createNativeQuery("Native SQL Query");
       nativeQuery.executeUpdate();
   }
}

我得到了这个运行时异常

Caused by: javax.persistence.TransactionRequiredException: Executing an update/delete query
    at org.hibernate.query.internal.AbstractProducedQuery.executeUpdate(AbstractProducedQuery.java:1496) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_40]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_40]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_40]
    at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_40]
    at org.springframework.orm.jpa.SharedEntityManagerCreator$DeferredQueryInvocationHandler.invoke(SharedEntityManagerCreator.java:380) ~[spring-orm-5.0.7.RELEASE.jar:5.0.7.RELEASE]

但是注入DataBase并调用init函数就可以了！

@Component
public class TestClass {

    @Autowired
    private DataBase dataBase;

    @PostConstruct
    public void test() {
        dataBase.init();
    }
}

为什么会这样！这是错误还是有某些原因？