What is Weaving in Spring?
Weaving is the process of linking aspect with other application types or object to create an advised object. This can be performed at compile time, runtime and load time. In spring framework weaving is performed at runtime.
What is AOP Proxy?
AOP proxy is an object to implement the aspect contracts (advice method executions and so on). The AOP proxy is object is created by the AOP framework. In spring framework AOP proxy is JDK dynamic proxy or CGLIB proxy.
What is front controller in Spring MVC?
The Front Controller is basically a type of Design pattern which are being implemented in different framework (e.g. Struts and Spring MVC etc.).
In Spring MVC DispatcherServlet act as a Front Controller for the framework and responsible for intercepting every request and then dispatches/forwards request to appropriate controller. Configure the DispatcherServlet in the web.xml file of web application and request which we want to be handled by DispatcherServlet should be mapped using URL mapping.
For example all the requests ending with *.do will be handled by the DispatcherServlet.
<web-app>
<servlet>
<servlet-name>example</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>example</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
</web-app>
Difference between FileSystemResource and ClassPathResource.
In FileSystemResource you need to give the configuration file (i.e. spring-config.xml) relative to your project or the absolute location of the file.
In ClassPathResource spring looks for the file in the ClassPath so configuration (i.e. spring-config.xml) file should be included in the classpath. If spring-config.xml is in classpath, you can simply give the name of the file.
For Example: If your configuration file is at src/main/java/com/test/loadresource then your
FileSystemResource would be:
FileSystemResource resource = new FileSystemResource("src/main/java/com/test/loadresource/spring-config.xml");
And ClassPathResource would be :
ClassPathResource resource = new ClassPathResource("com/test/loadresource /spring-config.xml");
What is inner Bean Definition?
A bean definition added inside the property or constructor-arg elements are called inner bean.
- Example :
<bean id="outerbean" class="...">
<!-- instead of using a reference to a target bean, simply define the target bean inline -->
<property name="targetbean">
<bean class="com.example.Person"> <!-- this is the inner bean -->
<property name="name" value="XYZ"/>
<property name="age" value="35"/>
</bean>
</property>
</bean>
Give examples of how spring platform can be used by an application developer.
The spring platform can be used by an application developer in the following way :
Java method can be made to execute in a database transaction without having to deal with transaction APIs.
Local Java method can be made a remote procedure without having to deal with remote APIs.
Local Java method can be made a management operation without having to deal with JMX APIs.
Local Java method can be made a message handler without having to deal with JMS APIs.
What are the various ways of using spring?
There are various ways and forms in which springs can be used.
They are listed as follows:
1. Full-fledged Spring web app.
2. Spring middle-tier provides help of a third-party web framework.
3. Remote usage scenario: allow the system to be used to remotely use the resources from the server. The remote usage can be done to grab the data from the server or for troubleshooting the environment.
4. EJB -- Wrapping existing POJOs.
Specify the locations where spring can publish its artifacts.
Spring generally publishes its artifacts to four different places:
1. Community download site http://spring.io/downloads/community.
2. Maven Central, which is considered the default repository that Maven queries, and does not require any special configuration to use.
3. The Enterprise Bundle Repository (EBR), which is considered to be run by SpringSource and also hosts all the libraries that integrate with Spring.
4. Public Maven repository hosted on Amazon S3 for the development of snapshots and milestone releases. The jar file names are given in the same form as Maven Central, which makes it a useful place to get development versions of Spring to use with other libraries Spring Framework deployed in Maven Central.
Weaving is the process of linking aspect with other application types or object to create an advised object. This can be performed at compile time, runtime and load time. In spring framework weaving is performed at runtime.
What is AOP Proxy?
AOP proxy is an object to implement the aspect contracts (advice method executions and so on). The AOP proxy is object is created by the AOP framework. In spring framework AOP proxy is JDK dynamic proxy or CGLIB proxy.
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| VMWare Spring MVC Recently Asked Interview Questions Answers |
What is front controller in Spring MVC?
The Front Controller is basically a type of Design pattern which are being implemented in different framework (e.g. Struts and Spring MVC etc.).
In Spring MVC DispatcherServlet act as a Front Controller for the framework and responsible for intercepting every request and then dispatches/forwards request to appropriate controller. Configure the DispatcherServlet in the web.xml file of web application and request which we want to be handled by DispatcherServlet should be mapped using URL mapping.
For example all the requests ending with *.do will be handled by the DispatcherServlet.
<web-app>
<servlet>
<servlet-name>example</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>example</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
</web-app>
Difference between FileSystemResource and ClassPathResource.
In FileSystemResource you need to give the configuration file (i.e. spring-config.xml) relative to your project or the absolute location of the file.
In ClassPathResource spring looks for the file in the ClassPath so configuration (i.e. spring-config.xml) file should be included in the classpath. If spring-config.xml is in classpath, you can simply give the name of the file.
For Example: If your configuration file is at src/main/java/com/test/loadresource then your
FileSystemResource would be:
FileSystemResource resource = new FileSystemResource("src/main/java/com/test/loadresource/spring-config.xml");
And ClassPathResource would be :
ClassPathResource resource = new ClassPathResource("com/test/loadresource /spring-config.xml");
What is inner Bean Definition?
A bean definition added inside the property or constructor-arg elements are called inner bean.
- Example :
<bean id="outerbean" class="...">
<!-- instead of using a reference to a target bean, simply define the target bean inline -->
<property name="targetbean">
<bean class="com.example.Person"> <!-- this is the inner bean -->
<property name="name" value="XYZ"/>
<property name="age" value="35"/>
</bean>
</property>
</bean>
Give examples of how spring platform can be used by an application developer.
The spring platform can be used by an application developer in the following way :
Java method can be made to execute in a database transaction without having to deal with transaction APIs.
Local Java method can be made a remote procedure without having to deal with remote APIs.
Local Java method can be made a management operation without having to deal with JMX APIs.
Local Java method can be made a message handler without having to deal with JMS APIs.
What are the various ways of using spring?
There are various ways and forms in which springs can be used.
They are listed as follows:
1. Full-fledged Spring web app.
2. Spring middle-tier provides help of a third-party web framework.
3. Remote usage scenario: allow the system to be used to remotely use the resources from the server. The remote usage can be done to grab the data from the server or for troubleshooting the environment.
4. EJB -- Wrapping existing POJOs.
Specify the locations where spring can publish its artifacts.
Spring generally publishes its artifacts to four different places:
1. Community download site http://spring.io/downloads/community.
2. Maven Central, which is considered the default repository that Maven queries, and does not require any special configuration to use.
3. The Enterprise Bundle Repository (EBR), which is considered to be run by SpringSource and also hosts all the libraries that integrate with Spring.
4. Public Maven repository hosted on Amazon S3 for the development of snapshots and milestone releases. The jar file names are given in the same form as Maven Central, which makes it a useful place to get development versions of Spring to use with other libraries Spring Framework deployed in Maven Central.
Can we send an Object as the response of Controller handler method?
Yes we can, using @ResponseBody annotation. This is how we send JSON or XML based response in restful web services.
How to upload file in Spring MVC Application?
Spring provides built-in support for uploading files through MultipartResolver interface implementations. It’s very easy to use and requires only configuration changes to get it working. Obviously we would need to write controller handler method to handle the incoming file and process it.
How to validate form data in Spring Web MVC Framework?
Spring supports JSR-303 annotation based validations as well as provide Validator interface that we can implement to create our own custom validator. For using JSR-303 based validation, we need to annotate bean variables with the required validations.
For custom validator implementation, we need to configure it in the controller class.
What is Spring MVC Interceptor and how to use it?
Spring MVC Interceptors are like Servlet Filters and allow us to intercept client request and process it. We can intercept client request at three places – preHandle, postHandle and afterCompletion.
We can create spring interceptor by implementing HandlerInterceptor interface or by extending abstract class HandlerInterceptorAdapter.
We need to configure interceptors in the spring bean configuration file. We can define an interceptor to intercept all the client requests or we can configure it for specific URI mapping too.
What is Spring JdbcTemplate class and how to use it?
Spring Framework provides excellent integration with JDBC API and provides JdbcTemplate utility class that we can use to avoid bolier-plate code from our database operations logic such as Opening/Closing Connection, ResultSet, PreparedStatement etc.
Yes we can, using @ResponseBody annotation. This is how we send JSON or XML based response in restful web services.
How to upload file in Spring MVC Application?
Spring provides built-in support for uploading files through MultipartResolver interface implementations. It’s very easy to use and requires only configuration changes to get it working. Obviously we would need to write controller handler method to handle the incoming file and process it.
How to validate form data in Spring Web MVC Framework?
Spring supports JSR-303 annotation based validations as well as provide Validator interface that we can implement to create our own custom validator. For using JSR-303 based validation, we need to annotate bean variables with the required validations.
For custom validator implementation, we need to configure it in the controller class.
What is Spring MVC Interceptor and how to use it?
Spring MVC Interceptors are like Servlet Filters and allow us to intercept client request and process it. We can intercept client request at three places – preHandle, postHandle and afterCompletion.
We can create spring interceptor by implementing HandlerInterceptor interface or by extending abstract class HandlerInterceptorAdapter.
We need to configure interceptors in the spring bean configuration file. We can define an interceptor to intercept all the client requests or we can configure it for specific URI mapping too.
What is Spring JdbcTemplate class and how to use it?
Spring Framework provides excellent integration with JDBC API and provides JdbcTemplate utility class that we can use to avoid bolier-plate code from our database operations logic such as Opening/Closing Connection, ResultSet, PreparedStatement etc.