java.lang.ClassCastException：无法将java.lang.Class强制转换为java.lang.reflect.ParameterizedType

Question

I have created hierarchy of interface and classes using generic and messed up everything.
Topmost class is AbstractJpaEntity which is extended by all domain entity

@MappedSuperclass
@EntityListeners({AbstractJpaEntity.AbstractEntityListener.class})
@SuppressWarnings("serial")
public class AbstractJpaEntity implements Serializable

ProductTypeDomain class is like marker class to separate out few table entity.

@SuppressWarnings("serial")
@MappedSuperclass
@EntityListeners({ ProductTypeDomain.AbstractEntityListener.class })
public class ProductTypeDomain extends AbstractJpaEntity{}

Interface "GenericDao" definition

public interface GenericDao<T> {...

Abstract class GenericDaoImpl(this class has general purpose function like persist, merge)

public abstract class GenericDaoImpl<T extends AbstractJpaEntity> implements GenericDao<T> {...

Interface ProductTypeDao

public interface ProductTypeDao<T extends ProductTypeDomain> extends GenericDao<T> {

Spring repository class ProductTypeDaoImpl

@Repository("productTypeDao")
public class ProductTypeDaoImpl extends GenericDaoImpl implements ProductTypeDao
{....

In spring service class ProductManagerServiceimpl, I am autowiring repository productTypeDao

@Service("productManager")
public class ProductManagerServiceimpl implements ProductManagerService{
    @Autowired
    ProductTypeDao productTypeDao;

On running code, it is giving me following error

Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.jodo.cms.service.ProductManagerService com.jodo.cms.controllers.ProductController.productManager; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productManager': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.jodo.cms.dao.ProductTypeDao com.jodo.cms.service.impl.ProductManagerServiceimpl.productTypeDao; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productTypeDao' defined in file [/home/jodo/Server/Tomcat/webapps/jodocms/WEB-INF/classes/com/jodo/cms/dao/impl/ProductTypeDaoImpl.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.jodo.cms.dao.impl.ProductTypeDaoImpl]: Constructor threw exception; nested exception is java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType

Full Stacktrace is
-------------------------------
09:24:29,443  INFO XmlWebApplicationContext:1020 - Closing Root WebApplicationContext: startup date [Tue Apr 15 08:38:10 IST 2014]; root of context hierarchy
09:24:29,445  INFO DefaultListableBeanFactory:433 - Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@153a859b: defining beans [org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.annotation.internalPersistenceAnnotationProcessor,productTypeDao,productEntityDao,productCategoryDao,categoryTreeDao,categoryEntityDao,categoryManager,productManager,dataSource,entityManagerFactory,transactionManager,org.springframework.aop.config.internalAutoProxyCreator,org.springframework.transaction.annotation.AnnotationTransactionAttributeSource#0,org.springframework.transaction.interceptor.TransactionInterceptor#0,org.springframework.transaction.config.internalTransactionAdvisor,log4jInitialization,org.springframework.context.annotation.ConfigurationClassPostProcessor$ImportAwareBeanPostProcessor#0]; root of factory hierarchy
09:24:29,460  INFO LocalContainerEntityManagerFactoryBean:441 - Closing JPA EntityManagerFactory for persistence unit 'default'
09:24:29,461  INFO SessionFactoryImpl:927 - closing
09:24:41,129  INFO DefaultListableBeanFactory:433 - Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@c27de92: defining beans [productController,categoryController,org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.annotation.internalPersistenceAnnotationProcessor,org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping#0,org.springframework.format.support.FormattingConversionServiceFactoryBean#0,org.springframework.validation.beanvalidation.LocalValidatorFactoryBean#0,org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter#0,org.springframework.web.servlet.handler.MappedInterceptor#0,org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver#0,org.springframework.web.servlet.mvc.annotation.ResponseStatusExceptionResolver#0,org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver#0,org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping,org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter,org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter,org.springframework.context.annotation.ConfigurationClassPostProcessor$ImportAwareBeanPostProcessor#0]; parent: org.springframework.beans.factory.support.DefaultListableBeanFactory@5803bbcc
09:24:41,134 ERROR DispatcherServlet:457 - Context initialization failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.jodo.cms.service.ProductManagerService com.jodo.cms.controllers.ProductController.productManager; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productManager': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.jodo.cms.dao.ProductTypeDao com.jodo.cms.service.impl.ProductManagerServiceimpl.productTypeDao; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productTypeDao' defined in file [/home/jodo/Server/Tomcat/webapps/jodocms/WEB-INF/classes/com/jodo/cms/dao/impl/ProductTypeDaoImpl.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class 

    [com.jodo.cms.dao.impl.ProductTypeDaoImpl]: Constructor threw exception; nested exception is java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:287)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1106)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:517)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
        at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294)
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225)
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:585)
        at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:913)
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:464)
        at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:631)
        at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:588)
        at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:645)
        at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:508)
        at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:449)
        at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:133)
        at javax.servlet.GenericServlet.init(GenericServlet.java:158)
        at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1279)
        at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1192)
        at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1087)
        at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:5210)
        at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5493)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
        at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
        at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
        at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:632)
        at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:1073)
        at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1857)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
        at java.util.concurrent.FutureTask.run(FutureTask.java:262)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:744)
    Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.jodo.cms.service.ProductManagerService com.jodo.cms.controllers.ProductController.productManager; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productManager': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.jodo.cms.dao.ProductTypeDao com.jodo.cms.service.impl.ProductManagerServiceimpl.productTypeDao; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productTypeDao' defined in file [/home/jodo/Server/Tomcat/webapps/jodocms/WEB-INF/classes/com/jodo/cms/dao/impl/ProductTypeDaoImpl.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.jodo.cms.dao.impl.ProductTypeDaoImpl]: Constructor threw exception; nested exception is java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:506)
        at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:284)
        ... 33 more
    Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productManager': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.jodo.cms.dao.ProductTypeDao com.jodo.cms.service.impl.ProductManagerServiceimpl.productTypeDao; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productTypeDao' defined in file [/home/jodo/Server/Tomcat/webapps/jodocms/WEB-INF/classes/com/jodo/cms/dao/impl/ProductTypeDaoImpl.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.jodo.cms.dao.impl.ProductTypeDaoImpl]: Constructor threw exception; nested exception is java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:287)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1106)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:517)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
        at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294)
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225)
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:269)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:848)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:790)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:707)
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:478)
        ... 35 more
    Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.jodo.cms.dao.ProductTypeDao com.jodo.cms.service.impl.ProductManagerServiceimpl.productTypeDao; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productTypeDao' defined in file [/home/jodo/Server/Tomcat/webapps/jodocms/WEB-INF/classes/com/jodo/cms/dao/impl/ProductTypeDaoImpl.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.jodo.cms.dao.impl.ProductTypeDaoImpl]: Constructor threw exception; nested exception is java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:506)
        at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:284)
        ... 48 more
    Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productTypeDao' defined in file [/home/jodo/Server/Tomcat/webapps/jodocms/WEB-INF/classes/com/jodo/cms/dao/impl/ProductTypeDaoImpl.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.jodo.cms.dao.impl.ProductTypeDaoImpl]: Constructor threw exception; nested exception is java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:997)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:943)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:485)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
        at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294)
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225)
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:848)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:790)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:707)
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:478)
        ... 50 more
    Caused by: org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.jodo.cms.dao.impl.ProductTypeDaoImpl]: Constructor threw exception; nested exception is java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType
        at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:162)
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:76)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:990)
        ... 61 more
    Caused by: java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType
        at com.jodo.cms.dao.impl.GenericDaoImpl.<init>(GenericDaoImpl.java:42)
        at com.jodo.cms.dao.impl.ProductTypeDaoImpl.<init>(ProductTypeDaoImpl.java:19)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
        at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:147)
        ... 63 more

class GenericDaoImpl details

public abstract class GenericDaoImpl<T extends AbstractJpaEntity> implements GenericDao<T> {
protected Class<T> entityClass;
Logger logger = Logger.getLogger(GenericDaoImpl.class);
@PersistenceContext
protected EntityManager em;
    public EntityManager getEntityManager() {
        return this.em;
    }
    @SuppressWarnings("unchecked")
    public GenericDaoImpl() {
        ParameterizedType genericSuperclass = (ParameterizedType) getClass().getGenericSuperclass();
        this.entityClass = (Class<T>) genericSuperclass.getActualTypeArguments()[0];
    }

public void persist(T entity) throws JodoException {
    try {
        em.persist(entity);
        em.flush();
    } catch (ConstraintViolationException cve) {
        throw new JodoException(cve.getCause(), "constraints violated", cve);
    }
}...

I cannot change AbstractJpaEntity, GenericDao and GenericDaoImpl, as it is already used for merging many other entities which are not extending ProductTypeDomain.

Thanks

Answer 1

In this class declaration

public class ProductTypeDaoImpl extends GenericDaoImpl implements ProductTypeDao

you're using GenericDaoImpl and ProductTypeDao as raw types. Start by reading why you shouldn't use them.

The fact that you are using raw types causes problems here

ParameterizedType genericSuperclass = (ParameterizedType) getClass().getGenericSuperclass();

where getGenericSuperclass() will return a Class instance since GenericDaoImpl , in

public class ProductTypeDaoImpl extends GenericDaoImpl implements ProductTypeDao

is not parameterized and therefore isn't a ParameterizedType . The cast then fails.

The solution is to parameterize the two types in your class declaration. It's not immediately obvious from your code what those type arguments should be, but GenericTypeDao should probably take ProductTypeDomain

public class ProductTypeDaoImpl extends GenericDaoImpl<ProductTypeDomain> implements ProductTypeDao

and your interface ProductTypeDao should probably be declared as

public interface ProductTypeDao extends GenericDao<ProductTypeDomain> {

Answer 2

This is a solution

public TO getTo() throws Exception {
    if(to == null) {
        try {
            to = ((Class<TO>) ((ParameterizedType) this.getClass().getGenericSuperclass())
                    .getActualTypeArguments()[0]).newInstance();
        } catch(ClassCastException cce) {
            cce.printStackTrace();
            to = ((Class<TO>) ((ParameterizedType) (((Class<TO>) this.getClass()
                    .getAnnotatedSuperclass().getType()).getGenericSuperclass()))
                            .getActualTypeArguments()[0]).newInstance();
        }
    }
    return to;
}