Himai Minh

Hi, in Spring doc

Spring recommends that you only annotate concrete classes (and methods of concrete classes) with the @Transactional annotation, as opposed to annotating interfaces. You certainly can place the @Transactional annotation on an interface (or an interface method), but this works only as you would expect it to if you are using interface-based proxies. The fact that Java annotations are not inherited from interfaces means that if you are using class-based proxies (proxy-target-class="true") or the weaving-based aspect (mode="aspectj"), then the transaction settings are not recognized by the proxying and weaving infrastructure, and the object will not be wrapped in a transactional proxy, which would be decidedly bad.

It mentions "Java annotation are not inherited from interfaces".
But @Transactional API is meta-annotated by @Inherited. It can be inherited by children classes.
If that is the case, "Java annotation are not inherited from interfaces.... then the transaction settings are not recognized by the proxy" is not true for @Transactional.
Do you think this Spring doc needs to be updated?

I would like to ask you for opinion before I ask the Spring community.

I would recommend the Spring Community to update this part of the document.
But don't know any one from the community.

In this section, we have this :

The required attribute of @Autowired is recommended over the @Required annotation on setter methods.
The required attribute indicates that the property is not required for autowiring purposes. The property is ignored if it cannot be autowired.
...

I think it should be "required=false attribute indicates that the property is not required for autowiring purpose.

Hi,
I found you a simple example of replace web.xml by a Java class. The class extends AbstractAnnotationConfigDispatcherServletInitializer. In this class, you can specify the servlet config and root config.
https://www.mkyong.com/spring-mvc/gradle-spring-4-mvc-hello-world-example-annotation/

Another example is here:
https://www.boraji.com/spring-4-mvc-hello-world-example

By the way, as I checked the API in org.springframework.transaction.annotation, @Transactional annotation has a meta-annotation @Inherited. That means this annotation can be inherited from interface. The class that implemented with an interface annotated with @Transactional should be able to create a transaction in AOP framework.
But I don't know why the Spring doc says the class based proxy won't see the @Transactional.

First, do you see a pop up message like the first JPG when you open your Spring_Config.xml?
If so, click on the "Configure application context" link.
Then, you will see a checkbox next to the file path. Click on it , just like my second JPG.

Hi,
Maybe, try to open your Spring_Config.xml file, and see if there is a pop up message telling your to add this config file to the application context. If so, click on it and see.
Then, clean your project and compile it.
I guess your current problem is that the bean is not registered in the application context.

Hi,
In Spring doc, it says

"Spring recommends that you only annotate concrete classes (and methods of concrete classes) with the @Transactional annotation, as opposed to annotating interfaces. You certainly can place the @Transactional annotation on an interface (or an interface method), but this works only as you would expect it to if you are using interface-based proxies. The fact that Java annotations are not inherited from interfaces means that if you are using class-based proxies (proxy-target-class="true") or the weaving-based aspect (mode="aspectj"), then the transaction settings are not recognized by the proxying and weaving infrastructure, and the object will not be wrapped in a transactional proxy, which would be decidedly bad.

I have a question regarding to the interface-based proxy and how it can see the @Transaction.
Suppose I have :
@Transactional public interface BankService{   public void openAccount(); }
@Service   public class GoodBankService implements BankSerivce{    public void openAccount(){         //do some account opening tasks here....  }

During runtime, the Spring AOP framework will generate a proxy for the GoodBankService:
public class GoodBankServiceProxy implementsBankService{   public void openAccount () {          //1. create a transaction         // 2. call the GoodBankService's openAccount();        //  3. commit the transaction   } }

According to the Spring doc above, putting @Transactional annoation in the interface works for the interfaced-based proxy (GoodBankServiceProxy). But it also says "Java annotations are not inherited from interfaces..."

My question is if GoodBankServiceProxy class does not inherit the @Transactional annotation from the BankService interface, how can this proxy execute the target object's openAccount method in the transaction ?

Hi,
Maybe, try to put your Spring_Config.xml under resource/META_INF/config folder.
After you compile it, make sure under target/classes/META-INFO/config folder has your Spring_Config.xml

I guess the reason why your bean is not found because the Spring_config.xml is not in the target/classes/META-INFO folder.

Hi, Labzar,
Is there any Spring Practice Exam desktop version?
The one you shared with us is on Android.

Hi,
From the Pivotal's study guide of Spring 5 professional certification exam, I don't see it mention Spring WebFlux or reactive programming which are new to Spring 5.
Are they on the exam?
Just want to confirm with some of you who took the exam.

Hi, Dominik,
I just bought your tutorial module 1 and I am studying on it  now
I can't wait to see module 2 - 8 available. Would you mind posting them soon?
Thanks.

Hi, I came across two examples from Spring in Action and Getting Started with Spring Framework.
One example uses new ClassPathXmlApplicationContext ("META-INFO/spring/knight.xml") and the other one uses new ClassPathXmlApplication("classpath:META-INFO/spring/applicationContext.xml")
Both knight.xml and applicationContext.xml are in resources/META-INFO/spring.
Both example works
I assume classpath prefix is always needed as the xml config file is under resources/META-INFO folder.
But why the classpath is needed in one example, but not the other?
The examples are here:
https://github.com/habuma/spring-in-action-4-samples/blob/master/Chapter_01/knight/src/main/java/sia/knights/KnightMain.java
https://github.com/getting-started-with-spring/4thEdition/blob/master/chapter%206/ch06-bean-profiles/src/main/java/sample/spring/chapter06/bankapp/BankAppWithProfile.java

Thanks in advance.

Hi, I find a fix to my code, but I don't think my fix is perfect. If anyone has a better solution, please let me know.
In the applicationContext.xml, I add the viewResolver:
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/mvc  http://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context        http://www.springframework.org/schema/context/spring-context.xsd"> <mvc:annotation-driven /> <context:component-scan base-package="sample.spring.chapter12" />       <!-- I have to add this to make it work, but it is only supposed to be in the bankapp-servlet.xml --> <bean id="viewResolver"  class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/jsp/" /> <property name="suffix" value=".jsp" /> </bean> </beans>

This is my bankapp-servlet.xml
<beans xmlns="http://www.springframework.org/schema/beans"   xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context"   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"   xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/mvc        http://www.springframework.org/schema/mvc/spring-mvc.xsd  http://www.springframework.org/schema/context        http://www.springframework.org/schema/context/spring-context.xsd "> <mvc:annotation-driven /> <context:component-scan base-package="sample.spring.chapter12.web" /> <bean id="viewResolver"  class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/jsp/" /> <property name="suffix" value=".jsp" /> </bean> </beans>

I committed my code there :
https://github.com/aCodeRancher/4thEdition/tree/my-bank-app/chapter%2012/ch12-bankapp

Hi, I am trying to replace web.xml in ch12-bankapp example of Getting Started With SpringFramework 4th edition.
This is the web.xml provided in the book:
<context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath*:/META-INF/spring/applicationContext.xml </param-value> </context-param> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener </listener-class> </listener> <servlet> <servlet-name>bankapp</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet </servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/spring/bankapp-config.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>bankapp</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping>

I converted it into Java code:
public class MyXMLWebAppInitializer implements WebApplicationInitializer {    @Override    public void onStartup (ServletContext container)  {         XmlWebApplicationContext   appContext = new XmlWebApplicationContext();        appContext.setConfigLocation("classpath*:/META-INF/spring/applicationContext.xml");            appContext.setServletContext(container);              DispatcherServlet theDispatcherServlet = new DispatcherServlet(appContext);         //I change the name of bankapp-config.xml to bankapp-servlet.xml        theDispatcherServlet.setContextConfigLocation("/WEB-INF/spring/bankapp-servlet.xml");        ServletRegistration.Dynamic theServletRegistration =               container.addServlet("bankapp", theDispatcherServlet);        theServletRegistration.setLoadOnStartup(1);        theServletRegistration.addMapping("/");    } }


This is the Tomcat 9 log :
 29-Mar-2019 21:40:45.061 INFO [RMI TCP Connection(3)-127.0.0.1] org.apache.jasper.servlet.TldScanner.scanJars At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time. INFO  org.springframework.web.context.support.XmlWebApplicationContext - Refreshing Root WebApplicationContext: startup date [Fri Mar 29 21:40:46 EDT 2019]; root of context hierarchy INFO  org.springframework.beans.factory.xml.XmlBeanDefinitionReader - Loading XML bean definitions from URL [file:/C:/Users/Downloads/apache-tomcat-9.0.11/webapps/ch12/WEB-INF/classes/META-INF/spring/applicationContext.xml] INFO  org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping - Mapped "{[/fixedDeposit],methods=[POST],params=[fdAction=edit]}" onto public org.springframework.web.servlet.ModelAndView sample.spring.chapter12.web.FixedDepositController.editFixedDeposit(org.springframework.util.MultiValueMap<java.lang.String, java.lang.String>) INFO  org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping - Mapped "{[/fixedDeposit],methods=[POST],params=[fdAction=create]}" onto public org.springframework.web.servlet.ModelAndView sample.spring.chapter12.web.FixedDepositController.openFixedDeposit(java.util.Map<java.lang.String, java.lang.String>) INFO  org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping - Mapped "{[/fixedDeposit/list],methods=[GET]}" onto public org.springframework.web.servlet.ModelAndView sample.spring.chapter12.web.FixedDepositController.listFixedDeposits() INFO  org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping - Mapped "{[/fixedDeposit],methods=[POST],params=[fdAction=createFDForm]}" onto public org.springframework.web.servlet.ModelAndView sample.spring.chapter12.web.FixedDepositController.showOpenFixedDepositForm() INFO  org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping - Mapped "{[/fixedDeposit],methods=[GET],params=[fdAction=close]}" onto public java.lang.String sample.spring.chapter12.web.FixedDepositController.closeFixedDeposit(int) INFO  org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping - Mapped "{[/fixedDeposit],methods=[GET],params=[fdAction=view]}" onto public org.springframework.web.servlet.ModelAndView sample.spring.chapter12.web.FixedDepositController.viewFixedDepositDetails(javax.servlet.http.HttpServletRequest) INFO  org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter - Looking for @ControllerAdvice: Root WebApplicationContext: startup date [Fri Mar 29 21:40:46 EDT 2019]; root of context hierarchy INFO  org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter - Looking for @ControllerAdvice: Root WebApplicationContext: startup date [Fri Mar 29 21:40:46 EDT 2019]; root of context hierarchy INFO  org.springframework.web.servlet.DispatcherServlet - FrameworkServlet 'bankapp': initialization started INFO  org.springframework.web.servlet.DispatcherServlet - FrameworkServlet 'bankapp': initialization completed in 123 ms [2019-03-29 09:40:50,280] Artifact ch12-bankapp:war: Artifact is deployed successfully [2019-03-29 09:40:50,280] Artifact ch12-bankapp:war: Deploy took 8,847 milliseconds 29-Mar-2019 21:40:51.080 INFO [ContainerBackgroundProcessor[StandardEngine[Catalina]]] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory [C:\Users\Downloads\apache-tomcat-9.0.11\webapps\manager] 29-Mar-2019 21:40:51.211 INFO [ContainerBackgroundProcessor[StandardEngine[Catalina]]] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory [C:\Users\Downloads\apache-tomcat-9.0.11\webapps\manager] has finished in [131] ms WARN  org.springframework.web.servlet.PageNotFound - No mapping found for HTTP request with URI [/ch12/fixedDeposit/fixedDepositList] in DispatcherServlet with name 'bankapp'

I cannot get any result from the browser.
If anyone knows, please help. Thanks.
This is my detailed code in GitHub:
https://github.com/aCodeRancher/4thEdition/tree/master/chapter%2012/ch12-bankapp