@Configuration
@ComponentScan("com.caveatemptor")
@EnableJpaRepositories
@EnableTransactionManagement
public class SpringDataJPAConfiguration {

    private Logger LOG = LoggerFactory.getLogger(SpringDataJPAConfiguration.class);

    // @Bean(destroyMethod = "close")
    // public BasicDataSource dataSource() {
    // BasicDataSource basicDataSource = new BasicDataSource();
    // basicDataSource.setDriverClassName("com.mysql.jdbc.Driver");
    // basicDataSource.setUrl("jdbc:mysql://localhost/ce");
    // basicDataSource.setUsername("root");
    // basicDataSource.setPassword("root");
    // basicDataSource.setInitialSize(1);
    // basicDataSource.setMaxIdle(5);
    // basicDataSource.setMaxOpenPreparedStatements(10);
    // LOG.debug("+++++++++++++Datasource Configured");
    // return basicDataSource;
    // }

    @Bean
    public DriverManagerDataSource dataSource() {
        DriverManagerDataSource basicDatasource = new DriverManagerDataSource();
        basicDatasource.setDriverClassName("com.mysql.jdbc.Driver");
        basicDatasource.setUrl("jdbc:mysql://localhost/ce");
        basicDatasource.setUsername("root");
        basicDatasource.setPassword("root");
        LOG.debug("+++++++++++++Datasource Configured");
        return basicDatasource;
    }

    // @Bean
    // public LocalContainerEntityManagerFactoryBean entityManager() {
    // LocalContainerEntityManagerFactoryBean bean = new
    // LocalContainerEntityManagerFactoryBean();
    // bean.setDataSource(this.dataSource());
    // bean.setLoadTimeWeaver(this.instrumentationLoadTimeWeaver());
    // bean.setJpaProperties(this.jpaProperties());
    // bean.setJpaVendorAdapter(this.vendorAdapter());
    // bean.setPersistenceProviderClass(HibernatePersistenceProvider.class);
    // bean.setPackagesToScan("com.caveatemptor.core");
    // bean.setPersistenceUnitName("jpwh");
    // LOG.info("==================[Entity Manage Configured]==================");
    // return bean;
    // }

    @Bean
    public HibernateJpaVendorAdapter vendorAdapter() {
        HibernateJpaVendorAdapter adapter = new HibernateJpaVendorAdapter();
        adapter.setShowSql(true);
        adapter.setGenerateDdl(true);
        LOG.info("==================[Hibernate Jpa Vendor Configured]==================");
        return adapter;
    }

    @Bean
    public PlatformTransactionManager transactionManager() {

        JpaTransactionManager jpaTransactionManager = new JpaTransactionManager();
        jpaTransactionManager.setDataSource(this.dataSource());
        jpaTransactionManager.setJpaProperties(this.jpaProperties());

        // jpaTransactionManager.setEntityManagerFactory(this.entityManager().getObject());
        return jpaTransactionManager;
    }

    @Bean
    public InstrumentationLoadTimeWeaver instrumentationLoadTimeWeaver() {
        return new InstrumentationLoadTimeWeaver();
    }

    public Properties jpaProperties() {
        Properties properties = new Properties();
        properties.setProperty("hibernate.hbm2ddl.auto", "create");
        properties.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQL5InnoDBDialect");
        properties.setProperty("hibernate.show_sql", "true");
        properties.setProperty("hibernate.format_sql", "true");
        properties.setProperty("hibernate.ejb.naming_strategy", "org.hibernate.cfg.DefaultNamingStrategy");
        properties.setProperty("hibernate.order_by.default_null_ordering", "first");
        LOG.info("==================[JPA Properties Configured]==================");
        return properties;
    }

    @Bean
    public SessionFactory sessionFactory() {
        LocalSessionFactoryBuilder bean = new LocalSessionFactoryBuilder(this.dataSource());
        bean.setProperties(this.jpaProperties());
        bean.addPackage("com.ceveatemptor");
        LOG.info("Session Factory Configured+++++++++++++++++++");
        return bean.buildSessionFactory();
    }
}

public class DispatcherServletInitConfiguration extends AbstractAnnotationConfigDispatcherServletInitializer {

    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class[] { SpringDataJPAConfiguration.class };
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[] { WebServletInitConfiguration.class };
    }

    @Override
    protected String[] getServletMappings() {
        return new String[] { "/" };
    }

}

public abstract class GenericDAOImpl<T, ID extends Serializable> implements GenericDAO<T, ID> {
@PersistenceContext
    protected EntityManager em;

    protected final Class<T> entityClass;

    public GenericDAOImpl(Class<T> entityClass) {
        this.entityClass = entityClass;
    }
@Override
    public T makePersistent(T entity) {
        return em.merge(entity);
    }
}

@Repository
@Transactional
@javax.transaction.Transactional
public class ItemDAOImpl extends GenericDAOImpl<Item, Long> implements ItemDAO {
    public ItemDAOImpl() {
        super(Item.class);
    }
}

Sep 02, 2017 11:30:22 AM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [dispatcher] in context with path [/portal] threw exception [Request processing failed; nested exception is javax.persistence.TransactionRequiredException: No EntityManager with actual transaction available for current thread - cannot reliably process 'merge' call] with root cause
javax.persistence.TransactionRequiredException: No EntityManager with actual transaction available for current thread - cannot reliably process 'merge' call
    at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:282)
    at com.sun.proxy.$Proxy77.merge(Unknown Source)
    at com.caveatemptor.core.dao.GenericDAOImpl.makePersistent(GenericDAOImpl.java:53)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:333)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207)
    at com.sun.proxy.$Proxy79.makePersistent(Unknown Source)
    at com.caveatemptor.web.controllers.ItemController.saveItem(ItemController.java:38)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)