October 11, 2018

Sreekanth B

Luxoft Most Frequently Asked Spring MVC Latest Interview Questions Answers

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.
Luxoft Most Frequently Asked Spring MVC Latest Interview Questions Answers
Luxoft Most Frequently Asked Spring MVC Latest Interview Questions Answers

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.

What is Aspect Oriented Programming (AOP)?

- Basically Aspect oriented programming complements object oriented programming by providing another way of programming model structure.
- In addition to classes, AOP gives you aspect, which enables modularization of concerns such as Transaction management or logging and can be separated out from the application business logic of the code (these kinds of concerns are termed as crosscutting concerns). AOP supports separating application business logic from System services.

What is IOC or Dependency Injection?

The basic concept of IOC (Dependency of Injection) is that you do not create your objects but describe how they should be created.

You don’t directly connect your component and services together in code but describe which services are needed by which component in configuration file.

You just need to describe the dependency, the Spring container is then responsible for hooking it all up.

When to use Dependency Injections?

There are different scenarios where you Dependency Injections are useful.

- You need to inject configuration data into one or more component.
- You need to inject the same dependency into multiple components.
- You need to inject different implementation of the same dependency.
- You need to inject the same implementation in different configuration.
- You need some of the services provided by container.

When you should not use Dependency Injection?

There were scenarios where you don’t need dependency injections e.g.
- You will never need a different implementation.
- You will never need different configurations.

What is Bean Factory in Spring?

- A Bean Factory is like a factory class that contains collections of beans. The Bean Factory holds bean definition of multiple beans within itself and then instantiates the bean when asked by client.
- Bean Factory is actual representation of the Spring IOC container that is responsible for containing and managing the configured beans.

Different Spring Bean Scope.

1. singleton : Return a single bean instance per Spring IOC container.
2. prototype : Return a new bean instance each time when requested.
3. request : Return a single bean instance per HTTP request.
4. session : Return a single bean instance per HTTP session.
5. global session : Return a single bean instance per global HTTP session and only valid when used in portlet context.

How you will decide when to use prototype scope and when singleton scope bean?

- You should use the prototype scope for all beans that are stateful and the singleton scope should be used for stateless beans.

What are the different types of IOC?

There are three types of dependency Injection:

1. Constructor Injection :

- Dependencies are provided as a constructor parameter.

- Example : You want to inject some object say 'Foo' through constructor in class 'HellowWorld' like below.
public class HelloWorld
{
public HelloWorld(Foo foo)
   {
       this.foo = foo;
   }
}

- In configuration file you need to do following entry.
<bean id="helloWorldBean" class="com.xyz.services.HelloWorld">
<constructor-arg ref="fooBean" />
</bean>
<bean id="fooBean" class="com.xyz.service.Foo">
</bean>

2. Setter Injection :

- Dependencies are assigned through setter method.

- Example : Same example as above.
public class HelloWorld
{
private Foo fooBean;
public HelloWorld(){ }
public void setFooBean(Foo fooBean)
{
   this.fooBean=fooBean;
}

- And in configuration file you need to do following entry.
<bean id="helloWorldBean" class=" com.xyz.services.HelloWorld">
<property name=fooBean ref="fooBean" />
</bean>
<bean id="fooBean" class="com.xyz.service.Foo">
</bean>

3. Interface Injection :

Injection is done through an interface and not supported in spring framework.
How to Call Stored procedure in Spring Framework?

- To call a Stored procedure in Spring framework you need to create Class which will should extends StoredProcedure class.
- Take the example of getting Employee Details by Employee Id. package com.mytest.spring.storeproc
import java.sql.ResultSet;
import java.sql.Types;
import java.util.HashMap;
import java.util.Map;
import javax.sql.DataSource;
import org.springframework.jdbc.core.SqlOutParameter;
import org.springframework.jdbc.core.SqlParameter;
import org.springframework.jdbc.object.StoredProcedure;
public class EmployeeInfo extends StoredProcedure
{
   private static final String EMP_ID = "EMP_ID";
   private static final String EMP_NAME = "EMP_NAME";
   private static final String JOIN_DATE = "JOIN_DATE";
   public SnapshotSearchStoredProcedure(DataSource dataSource, String procedureName)
   {
       super(dataSource, procedureName);
       declareParameter(new SqlParameter(EMP_ID, Types.NUMERIC));
       declareParameter(new SqlOutParameter(EMP_NAME, Types.VARCHAR));
       declareParameter(new SqlOutParameter(JOIN_DATE, Types.VARCHAR));
       compile ();
   }
   public Map execute(Integer empId)
   {
       Map<String, Object> inputs = new HashMap<String, Object>();
       inputs.put(P_CLD_IDR, empId);
       Map<String, Object> result = execute (inputs);
       return result;
   }
}
- You just need to call the execute method from the DAO layer.

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