Servlet interview questions
There is a list of 30 servlet
interview questions for beginners and professionals. If you know any servlet
interview question that has not been included here, kindly post your question
in the Ask Question section.
1) How many objects of a servlet is created?
Only one object at the time of
first request by servlet or web container.
2) What is the life-cycle of a servlet?
1. Servlet
is loaded
2. servlet
is instantiated
3. servlet
is initialized
4. service
the request
5. servlet
is destroyed
3) What are the life-cycle methods for a servlet?
|
Method
|
Description
|
|
public void init(ServletConfig config)
|
It is invoked only once when first request comes for the
servlet. It is used to initialize the servlet.
|
|
public void service(ServletRequest
request,ServletResponse)throws ServletException,IOException
|
It is invoked at each request.The service() method is used to
service the request.
|
|
public void destroy()
|
It is invoked only once when servlet is unloaded.
|
4) Who is responsible to create the object of servlet?
The web container or servlet
container.
5) When servlet object is created?
At the time of first request.
6) What is difference between Get and Post method?
|
Get
|
Post
|
|
1) Limited amount of data can be sent because data is sent in
header.
|
Large amount of data can be sent because data is sent in body.
|
|
2) Not Secured because data is exposed in URL bar.
|
Secured because data is not exposed in URL bar.
|
|
3) Can be bookmarked
|
Cannot be bookmarked
|
|
4) Idempotent
|
Non-Idempotent
|
|
5) It is more efficient and used than Post
|
It is less efficient and used
|
7) What is difference between PrintWriter and
ServletOutputStream?
PrintWriter is a
character-stream class where as ServletOutputStream is a byte-stream class. The
PrintWriter class can be used to write only character-based information whereas
ServletOutputStream class can be used to write primitive values as well as
character-based information.
8) What is difference between GenericServlet and
HttpServlet?
The GenericServlet is protocol
independent whereas HttpServlet is HTTP protocol specific. HttpServlet provides
additional functionalities such as state management etc.
9) What is servlet collaboration?
When one servlet communicates
to another servlet, it is known as servlet collaboration. There are many ways
of servlet collaboration:
- RequestDispacher interface
- sendRedirect() method etc.
10) What is the purpose of RequestDispatcher Interface?
The RequestDispacher interface
provides the facility of dispatching the request to another resource it may be
html, servlet or jsp. This interceptor can also be used to include the content
of antoher resource.
11) Can you call a jsp from the servlet?
Yes, one of the way is
RequestDispatcher interface for example:
1.
RequestDispatcher rd=request.getRequestDispatcher("/login.jsp");
2.
rd.forward(request,response);
12) Difference between forward() method and sendRedirect()
method ?
|
forward() method
|
sendRedirect() method
|
|
1) forward() sends the same request to another resource.
|
1) sendRedirect() method sends new request always because it
uses the URL bar of the browser.
|
|
2) forward() method works at server side.
|
2) sendRedirect() method works at client side.
|
|
3) forward() method works within the server only.
|
3) sendRedirect() method works within and outside the server.
|
13) What is difference between ServletConfig and ServletContext?
The container creates object of
ServletConfig for each servlet whereas object of ServletContext is created for
each web application.
14) What is Session Tracking?
Session simply
means a particular interval of time.
Session Tracking is a way to maintain
state of an user.Http protocol is a stateless protocol.Each time user requests
to the server, server treats the request as the new request.So we need to
maintain the state of an user to recognize to particular user.
15) What are Cookies?
A cookie is a small piece of
information that is persisted between the multiple client requests. A cookie
has a name, a single value, and optional attributes such as a comment, path and
domain qualifiers, a maximum age, and a version number.
16) What is difference between Cookies and HttpSession?
Cookie works at client side
whereas HttpSession works at server side.
17) What is filter?
A filter is an object that is
invoked either at the preprocessing or postprocessing of a request. It is
pluggable.
18) How can we perform any action at the time of deploying
the project?
By the help of
ServletContextListener interface.
19) What is the disadvantage of cookies?
It will not work if cookie is
disabled from the browser.
20) How can we upload the file to the server using servlet?
One of the way is by
MultipartRequest class provided by third party.
21) What is load-on-startup in servlet?
The load-on-startup element of
servlet in web.xml is used to load the servlet at the time of deploying the
project or server start. So it saves time for the response of first request.
22) What if we pass negative value in load-on-startup?
It will not affect the
container, now servlet will be loaded at first request.
23) What is war file?
A war (web archive) file
specifies the web elements. A servlet or jsp project can be converted into a
war file. Moving one servlet project from one place to another will be fast as
it is combined into a single file.
24) How to create war file?
The war file can be created
using jar tool found in jdk/bin directory. If you are using Eclipse or Netbeans
IDE, you can export your project as a war file.
To create war file from
console, you can write following code.
1.
jar -cvf abc.war *
Now all the files of current
directory will be converted into abc.war file.
25) What are the annotations used in Servlet 3?
There are mainly 3 annotations
used for the servlet.
1. @WebServlet
: for servlet class.
2. @WebListener
: for listener class.
3. @WebFilter
: for filter class.
26) Which event is fired at the time of project deployment
and undeployment?
ServletContextEvent.
27) Which event is fired at the time of session creation
and destroy?
HttpSessionEvent.
28) Which event is fired at the time of setting, getting or
removing attribute from application scope?
ServletContextAttributeEvent.
29) What is the use of welcome-file-list?
It is used to specify the
welcome file for the project.
30) What is the use of attribute in servlets?
Attribute is a map object that
can be used to set, get or remove in request, session or application scope. It
is mainly used to share information between one servlet to another.
Jsp Interview questions
There is a list of 25 jsp
interview questions for freshers and professionals. If you know any jsp
interview question that has not been included here, post your question in the
Ask Question section.
1)What is JSP?
Java Server Pages technology
(JSP) is used to create dynamic web page. It is an extension to the servlet
technology. A JSP page is internally converted into servlet.
2) What are the life-cycle methods for a jsp?
|
Method
|
Description
|
|
public void jspInit()
|
It is invoked only once, same as init method of servlet.
|
|
public void _jspService(ServletRequest request,ServletResponse)throws
ServletException,IOException
|
It is invoked at each request, same as service() method of
servlet.
|
|
public void jspDestroy()
|
It is invoked only once, same as destroy() method of servlet.
|
3)What is difference between hide comment and output comment?
The jsp comment is called hide
comment whereas html comment is called output comment. If user views the source
of the page, the jsp comment will not be shown whereas html comment will be
shown.
4)What are the JSP implicit objects ?
JSP provides 9 implicit objects
by default. They are as follows:
|
Object
|
Type
|
|
1) out
|
JspWriter
|
|
2) request
|
HttpServletRequest
|
|
3) response
|
HttpServletResponse
|
|
4) config
|
ServletConfig
|
|
5) session
|
HttpSession
|
|
6) application
|
ServletContext
|
|
7) pageContext
|
PageContext
|
|
8) page
|
Object
|
|
9) exception
|
Throwable
|
5)What is difference between include directive and include
action?
|
include directive
|
include action
|
|
1) The include directive includes the content at page
translation time.
|
1) The include action includes the content at request time.
|
|
2) The include directive includes the original content of the
page so page size increases at runtime.
|
2) The include action doesn't include the original content rather
invokes the include() method of Vendor provided class.
|
|
3) It's better for static pages.
|
3) It's better for dynamic pages.
|
6) Is JSP technology extensible?
Yes. JSP technology is
extensible through the development of custom actions, or tags, which are
encapsulated in tag libraries.
7) How can I implement a thread-safe JSP page? What are the
advantages and Disadvantages of using it?
You can make your JSPs
thread-safe by having them implement the SingleThreadModel interface. This is
done by adding the directive <%@ page isThreadSafe="false" %>
within your JSP page.
8) How can I prevent the output of my JSP or Servlet pages
from being cached by the browser?
(OR) How to disable caching on back button of the browser?
1.
<%
2.
response.setHeader("Cache-Control","no-store");
3.
response.setHeader("Pragma","no-cache");
4.
response.setHeader ("Expires", "0"); //prevents caching at the proxy server
5.
%>
9) How can we handle the exceptions in JSP ?
There are two ways to perform
exception handling, one is by the errorPage element of page directive, and
second is by the error-page element of web.xml file.
10) What are the two ways to include the result of another
page. ?
There are two ways to include
the result of another page:
11) How can we forward the request from jsp page to the
servlet ?
Yes ofcourse! With the help of
forward action tag, but we need to give the url-pattern of the servlet.
12) Can we use the exception implicit object in any jsp
page ?
No. The exception implicit
object can only be used in the error page which defines it with the isErrorPage
attribute of page directive.
13) How is JSP used in the MVC model?
JSP is usually used for
presentation in the MVC pattern (Model View Controller ) i.e. it plays the role
of the view. The controller deals with calling the model and the business
classes which in turn get the data, this data is then presented to the JSP for
rendering on to the client.
14) What are context initialization parameters?
Context initialization
parameters are specified by the <context-param> in the web.xml file,
these are initialization parameter for the whole application and not specific
to any servlet or JSP.
15) What are the different scope values for the
<jsp:useBean> tag?
There are 4 values:
1. page
2. request
3. session
4. application
16)What is the difference between ServletContext and
PageContext?-
ServletContext gives the
information about the container whereas PageContext gives the information about
the Request.
17)What is the difference in using
request.getRequestDispatcher() and context.getRequestDispatcher()?
request.getRequestDispatcher(path)
is used in order to create it we need to give the relative path of the resource
whereas context.getRequestDispatcher(path) in order to create it we need to
give the absolute path of the resource.
18) What is EL in JSP?
The Expression Language(EL) is
used in JSP to simplify the accessibility of objects. It provides many objects
that can be used directly like param, requestScope, sessionScope,
applicationScope, request, session etc.
19)What is basic differences between the JSP custom tags
and java beans?
- Custom tags can manipulate JSP content
whereas beans cannot.
- Complex operations can be reduced to a
significantly simpler form with custom tags than with beans.
- Custom tags require quite a bit more
work to set up than do beans.
- Custom tags are available only in JSP
1.1 and later, but beans can be used in all JSP 1.x versions.
20) Can an interface be implemented in the jsp file ?
No.
21) What is JSTL?
JSP Standard Tag Library is
library of predefined tags that ease the development of JSP.
22) How many tags are provided in JSTL?
There are 5 type of JSTL tags.
1. core
tags
2. sql tags
3. xml tags
4. internationalization
tags
5. functions
tags
23) Which directive is used in jsp custom tag?
The jsp taglib directive.
24) What are the 3 tags used in JSP bean development?
1. jsp:useBean
2. jsp:setProperty
3. jsp:getProperty
25) How to disable session in JSP?
1.
<%@ page session="false" %>
EJB Interview Questions
There is given EJB interview
questions and answers that has been asked in many companies. Let's see the list
of top EJB interview questions.
1) What is EJB?
EJB stands for Enterprise Java
Bean. It is a server-side component to develop scalable, robust and secured
enterprise applications in java. More
details...
2) What are the types of Enterprise Bean?
There are 3 types of enterprise
bean in java.
1. Session
Bean
2. Message
Driven Bean
3. Entity
Bean
3) What is session bean?
Session Bean encapsulates
business logic. It can be invoked by local, remote or web service client.
There are 3 types of session
bean.
1. Stateless
Session Bean
2. Stateful
Session Bean
3. Singleton
Session Bean
4) What is stateless session bean?
Stateless session bean is a
business object that doesn't maintain conversational state with the
client. More details...
5) What is stateful session bean?
Stateful session bean is a
business object that maintains conversational state with the client. More
details...
6) What is singleton session bean?
Singleton session bean is
instantiated only once for the application. It exists for the life cycle of the
application.
7) What is JMS?
Java Message Service is a
messaging service to create, send and receive messages asynchronously. More
details...
8) What are the advantages of JMS?
- Asynchronous
- Reliable
9) What is PTP model?
In Point to Point model, one
message is delivered to one receiver only. Here, Queue is used as a message
oriented middleware. More details...
10) What is Pub/Sub model?
In Publisher/Subscriber model,
one message is delivered to all subscribers. Here, Topic is used as a message
oriented middleware. More details...
11) What is MDB?
Message Driven Bean (MDB)
encapsulates business logic. It is invoked by passing message. It is like JMS
receiver. More details...
12) What is Entity Bean?
Entity Bean is a server side
component that represents the persistent data. Since EJB 3.x, it is replaced by
JPA. More details...
13) What is Session Facade?
Session Facade is a design pattern
to access enterprise bean through local interface. It abstracts the business
object interactions and provides a service layer. It makes the performance fast
over network.
Struts Interview Questions
There is given frequently asked
struts interview questions and answers that has been asked in many companies.
Let's see the list of top Struts2 interview questions.
1) What is Struts?
Struts is a framework for
developing MVC-based framework. Struts2 is the combination of Webwork and
struts1 frameworks. More details...
2) What is
the difference between struts1 and struts2?
|
No.
|
Struts1
|
Struts2
|
|
1)
|
Action class is not POJO. You need to inherit abstract class.
|
Action class is POJO. You don't need to inherit any class or
implement any interface.
|
|
2)
|
Front controller is ActionServlet.
|
Front Controller is StrutsPrepareAndExecuteFilter.
|
|
3)
|
It uses the concept of RequestProcessor class while processing
request.
|
It uses the concept of Interceptors while processing the
request.
|
|
4)
|
It has only JSP for the view component.
|
It has JSP, Freemarker, Valocity etc. for the view component.
|
|
5)
|
Configuration file name can be [anyname].xml and placed inside
WEB-INF directory.
|
Configuration file must be struts.xml and placed inside classes
directory.
|
|
6)
|
Action and Model are separate.
|
Action and Model are combined within action class.
|
3) What are the features of Struts?
- Configuration MVC components
- POJO based action
- AJAX Support
- Various Tag Support
- Various Result Types
- Integration Support
4) What is MVC?
MVC is a design pattern. MVC
stands for Model, View and Controller. Model represents data, view represents
presentation and controller acts as an interface between model and view.
5) What is interceptor?
Interceptor is an object i.e.
invoked at preprocessing and postprocessing of a request. It is
pluggable. More details...
6) What are the life cycle methods of interceptor?
- public void init()
- public void intercept(ActionInvocation
ai)
- public void destroy()
7) What is ValueStack?
ValueStack is a stack that
contains application specific object such as action and other model. More details...
8) What is ActionContext?
ActionContext is a container in
which action is executed. It is unique per thread. More details...
9) What is ActionInvocation?
ActionInvocation is responsible
to invoke action. It holds action and interceptor objects. More details...
10) What is OGNL?
OGNL is an expression language
of struts2. It stands for Object Graph Navigation Language. More details...
11) What are the 5 constants of Action interface?
1. SUCCESS
2. ERROR
3. INPUT
4. LOGIN
5. NONE
12) What does params interceptor?
The params (also known as
parameters) interceptor sets all parameters on the ValueStack. More details...
13) What does execAndWait interceptor?
The execAndWait (also known as
ExecuteAndWait) interceptor is used to display intermediate or wait
result. More details...
14) What does modelDriven interceptor?
The modelDriven interceptor
makes other model as the default object of ValueStack. By default, action is
the default object of ValueStack. More details...
15) What does validation interceptor?
The validation interceptor
performs validation checks and adds field-level and action-level error
messages. More details...
16) What are the bundled validators?
- requiredstring
- stringlength
- email
- date
- int
- double
- url
- regex
17) What is the difference between plain-validator and
field-validator?
In plain-validator one
validator can be applied to many fields. In field-validator many validators can
be applied to single field. More details...
18) What is the use of jsonValidation?
The jsonValidation interceptor
is used to perform asynchronous validation. It works with validation and
workflow interceptors. More details...
19) What are the aware interfaces in struts2?
Aware interfaces are used to
store information in request, session, application and response objects. The 4
aware interfaces are given below:
- ServletRequestAware
- ServletResponseAware
- SessionAware
- ServletContextAware
20) What does i18n interceptor?
The i18n interceptor is used to
provide multi lingual support for struts application. More details...
Hibernate Interview Questions
Hibernate interview questions
are asked to the students because it is a widely used ORM tool. The important
list of top 20 hibernate interview questions and answers for freshers and
professionals are given below.
1) What is hibernate?
Hibernate is an open-source and
lightweight ORM tool that is used to store, manipulate and retrieve data from
the database.
2) What is ORM?
ORM is an acronym for
Object/Relational mapping. It is a programming strategy to map object with the
data stored in the database. It simplifies data creation, data manipulation and
data access.
3) Explain hibernate architecture?
Hibernate architecture
comprises of many interfaces such as Configuration, SessionFactory, Session,
Transaction etc.
4) What are the core interfaces of Hibernate?
The core interfaces of
Hibernate framework are:
- Configuration
- SessionFactory
- Session
- Query
- Criteria
- Transaction
5) What is SessionFactory?
SessionFactory provides the
instance of Session. It is a factory of Session. It holds the data of second
level cache that is not enabled by default.
6) Is SessionFactory a thread-safe object?
Yes, SessionFactory is a
thread-safe object, many threads cannot access it simultaneously.
7) What is Session?
It maintains a connection
between hibernate application and database.
It provides methods to store,
update, delete or fetch data from the database such as persist(), update(),
delete(), load(), get() etc.
It is a factory of Query,
Criteria and Transaction i.e. it provides factory methods to return these
instances.
8) Is Session a thread-safe object?
No, Session is not a
thread-safe object, many threads can access it simultaneously. In other words,
you can share it between threads.
9) What is the difference between session.save() and
session.persist() method?
|
No.
|
save()
|
persist()
|
|
1)
|
returns the identifier (Serializable) of the instance.
|
return nothing because its return type is void.
|
|
2)
|
Syn: public Serializable save(Object o)
|
Syn: public void persist(Object o)
|
10) What is the difference between get and load method?
The differences between get()
and load() methods are given below.
|
No.
|
get()
|
load()
|
|
1)
|
Returns null if object is not found.
|
Throws ObjectNotFoundException if object is not
found.
|
|
2)
|
get() method always hit the database.
|
load() method doesn't hit the database.
|
|
3)
|
It returns real object not proxy.
|
It returns proxy object.
|
|
4)
|
It should be used if you are not sure about the
existence of instance.
|
It should be used if you are sure that instance
exists.
|
11) What is the difference between update and merge method?
The differences between
update() and merge() methods are given below.
|
No.
|
update() method
|
merge() method
|
|
1)
|
Update means to edit something.
|
Merge means to combine something.
|
|
2)
|
update() should be used if session doesn't contain an already
persistent state with same id. It means update should be used inside the
session only. After closing the session it will throw error.
|
merge() should be used if you don't know the state of the
session, means you want to make modification at any time.
|
Let's try to understand the
difference by the example given below:
1.
...
2.
SessionFactory factory = cfg.buildSessionFactory();
3.
Session session1 = factory.openSession();
4.
5.
Employee e1 = (Employee) session1.get(Employee.class, Integer.valueOf(101));//passing id of employee
6.
session1.close();
7.
8.
e1.setSalary(70000);
9.
10.
Session session2 = factory.openSession();
11.
Employee e2 = (Employee) session1.get(Employee.class, Integer.valueOf(101));//passing same id
12.
13.
Transaction tx=session2.beginTransaction();
14.
session2.merge(e1);
15.
16.
tx.commit();
17.
session2.close();
After closing session1, e1 is
in detached state. It will not be in session1 cache. So if you call update()
method, it will throw an error.
Then, we opened another session
and loaded the same Employee instance. If we call merge in session2, changes of
e1 will be merged in e2.
12) What are the states of object in hibernate?
There are 3 states of object
(instance) in hibernate.
1. Transient: The
object is in transient state if it is just created but has no primary key
(identifier) and not associated with session.
2. Persistent: The
object is in persistent state if session is open, and you just saved the
instance in the database or retrieved the instance from the database.
3. Detached: The
object is in detached state if session is closed. After detached state, object
comes to persistent state if you call lock() or update() method.
13) What are the inheritance mapping strategies?
There are 3 ways of inheritance
mapping in hibernate.
1. Table
per hierarchy
2. Table
per concrete class
3. Table
per subclass
14) How to make a immutable class in hibernate?
If you mark a class as
mutable="false", class will be treated as an immutable class. By
default, it is mutable="true".
15) What is automatic dirty checking in hibernate?
The automatic dirty checking
feature of hibernate, calls update statement automatically on the objects that
are modified in a transaction.
Let's understand it by the
example given below:
1.
...
2.
SessionFactory factory = cfg.buildSessionFactory();
3.
Session session1 = factory.openSession();
4.
Transaction tx=session2.beginTransaction();
5.
6.
Employee e1 = (Employee) session1.get(Employee.class, Integer.valueOf(101));
7.
8.
e1.setSalary(70000);
9.
10.
tx.commit();
11.
session1.close();
Here, after getting employee
instance e1 and we are changing the state of e1.
After changing the state, we
are committing the transaction. In such case, state will be updated
automatically. This is known as dirty checking in hibernate.
16) How many types of association mapping are possible in
hibernate?
There can be 4 types of
association mapping in hibernate.
1. One to
One
2. One to
Many
3. Many to
One
4. Many to
Many
17) Is it possible to perform collection mapping with
One-to-One and Many-to-One?
No, collection mapping can only
be performed with One-to-Many and Many-to-Many
18) What is lazy loading in hibernate?
Lazy loading in hibernate
improves the performance. It loads the child objects on demand.
Since Hibernate 3, lazy loading
is enabled by default, you don't need to do lazy="true". It means not
to load the child objects when parent is loaded.
19) What is HQL (Hibernate Query Language)?
Hibernate Query Language is
known as an object oriented query language. It is like structured query
language (SQL).
The main advantage of HQL over
SQL is:
1. You
don't need to learn SQL
2. Database
independent
3. Simple
to write query
20) What is the difference between first level cache and
second level cache?
|
No.
|
First Level Cache
|
Second Level Cache
|
|
1)
|
First Level Cache is associated with Session.
|
Second Level Cache is associated with SessionFactory.
|
|
2)
|
It is enabled by default.
|
It is not enabled by default.
|
Spring Interview Questions
Spring interview questions and
answers are frequently asked because it is now widely used framework to develop
enterprise application in java. There are given a list of top 40 frequently
asked spring interview questions.
1) What is Spring?
It is a lightweight, loosely
coupled and integrated framework for developing enterprise applications in
java.
2) What are the advantages of spring framework?
1. Predefined
Templates
2. Loose
Coupling
3. Easy to
test
4. Lightweight
5. Fast
Development
6. Powerful
Abstraction
7. Declarative
support
3) What are the modules of spring framework?
1. Test
2. Spring
Core Container
3. AOP,
Aspects and Instrumentation
4. Data
Access/Integration
5. Web
4) What is IOC and DI?
IOC (Inversion of Control) and
DI (Dependency Injection) is a design pattern to provide loose coupling. It
removes the dependency from the program.
Let's write a code without
following IOC and DI.
1.
public class Employee{
2.
Address address;
3.
Employee(){
4.
address=new Address();//creating instance
5.
}
6.
}
Now, there is dependency
between Employee and Address because Employee is forced to use the same address
instance.
Let's write the IOC or DI code.
1.
public class Employee{
2.
Address address;
3.
Employee(Address address){
4.
this.address=address;//not creating instance
5.
}
6.
}
Now, there is no dependency
between Employee and Address because Employee is not forced to use the same
address instance. It can use any address instance.
5) What is the role of IOC container in spring?
IOC container is responsible
to:
- create the instance
- configure the instance, and
- assemble the dependencies
6) What are the types of IOC container in spring?
There are two types of IOC
containers in spring framework.
1. BeanFactory
2. ApplicationContext
7) What is the difference between BeanFactory and ApplicationContext?
BeanFactory is the basic
container whereas ApplicationContext is the advanced container.
ApplicationContext extends the BeanFactory interface. ApplicationContext
provides more facilities than BeanFactory such as integration with spring AOP,
message resource handling for i18n etc.
8) What is the difference between constructor injection and
setter injection?
|
No.
|
Constructor Injection
|
Setter Injection
|
|
1)
|
No Partial Injection
|
Partial Injection
|
|
2)
|
Desn't override the setter property
|
Overrides the constructor property if both are defined.
|
|
3)
|
Creates new instance if any modification occurs
|
Doesn't create new instance if you change the property value
|
|
4)
|
Better for too many properties
|
Better for few properties.
|
9) What is autowiring in spring? What are the autowiring
modes?
Autowiring enables the
programmer to inject the bean automatically. We don't need to write explicit
injection logic.
Let's see the code to inject
bean using dependency injection.
1.
<bean id="emp" class="com.javatpoint.Employee" autowire="byName" />
The autowiring modes are given
below:
|
No.
|
Mode
|
Description
|
|
1)
|
no
|
this is the default mode, it means autowiring is not enabled.
|
|
2)
|
byName
|
injects the bean based on the property name. It uses setter
method.
|
|
3)
|
byType
|
injects the bean based on the property type. It uses setter
method.
|
|
4)
|
constructor
|
It injects the bean using constructor
|
The "autodetect" mode
is deprecated since spring 3.
10) What are the different bean scopes in spring?
There are 5 bean scopes in
spring framework.
|
No.
|
Scope
|
Description
|
|
1)
|
singleton
|
The bean instance will be only once and same instance will be
returned by the IOC container. It is the default scope.
|
|
2)
|
prototype
|
The bean instance will be created each time when requested.
|
|
3)
|
request
|
The bean instance will be created per HTTP request.
|
|
4)
|
session
|
The bean instance will be created per HTTP session.
|
|
5)
|
globalsession
|
The bean instance will be created per HTTP global session. It
can be used in portlet context only.
|
11) In which scenario, you will use singleton and prototype
scope?
Singleton scope should be used
with EJB stateless session bean and prototype scope with
EJB stateful session bean.
12) What are the transaction management supports provided
by spring?
Spring framework provides two
type of transaction management supports:
1. Programmatic
Transaction Management: should be used for few transaction operations.
2. Declarative
Transaction Management: should be used for many transaction operations.
» Spring JDBC Interview Questions
13) What are the advantages of JdbcTemplate in spring?
Less code: By
using the JdbcTemplate class, you don't need to create connection,statement,start
transaction,commit transaction and close connection to execute different
queries. You can execute the query directly.
14) What are classes for spring JDBC API?
1. JdbcTemplate
2. SimpleJdbcTemplate
3. NamedParameterJdbcTemplate
4. SimpleJdbcInsert
5. SimpleJdbcCall
15) How can you fetch records by spring JdbcTemplate?
You can fetch records from the
database by the query method of JdbcTemplate. There are two
interfaces to do this:
2. RowMapper
16) What is the advantage of NamedParameterJdbcTemplate?
NamedParameterJdbcTemplate
class is used to pass value to the named parameter. A named parameter is better
than ? (question mark of PreparedStatement).
It is better to
remember.
17) What is the advantage of SimpleJdbcTemplate?
The SimpleJdbcTemplate supports
the feature of var-args and autoboxing.
» Spring AOP Interview Questions
18) What is AOP?
AOP is an acronym for Aspect
Oriented Programming. It is a methodology that divides the program logic into
pieces or parts or concerns.
It increases the modularity and
the key unit is Aspect.
19) What are the advantages of spring AOP?
AOP enables you to dynamically
add or remove concern before or after the business logic. It is pluggable and easy
to maintain.
20) What are the AOP terminology?
AOP terminologies or concepts
are as follows:
- JoinPoint
- Advice
- Pointcut
- Aspect
- Introduction
- Target Object
- Interceptor
- AOP Proxy
- Weaving
21) What is JoinPoint?
JoinPoint is any point in your
program such as field access, method execution, exception handling etc.
22) Does spring framework support all JoinPoints?
No, spring framework supports
method execution joinpoint only.
23) What is Advice?
Advice represents action taken
by aspect.
24) What are the types of advice in AOP?
There are 5 types of advices in
spring AOP.
1. Before
Advice
2. After
Advice
3. After
Returning Advice
4. Throws
Advice
5. Around
Advice
25) What is Pointcut?
Pointcut is expression language
of Spring AOP.
26) What is Aspect?
Aspect is a class in spring AOP
that contains advices and joinpoints.
27) What is Introduction?
Introduction represents
introduction of new fields and methods for a type.
28) What is target object?
Target Object is a proxy object
that is advised by one or more aspects.
29) What is interceptor?
Interceptor is a class like
aspect that contains one advice only.
30) What is weaving?
Weaving is a process of linking
aspect with other application.
31) Does spring perform weaving at compile time?
No, spring framework performs
weaving at runtime.
32) What are the AOP implementation?
There are 3 AOP implementation.
1. Spring
AOP
2. Apache
AspectJ
3. JBoss
AOP
» Spring MVC Interview Questions
33) What is the front controller class of Spring MVC?
The DispatcherServlet class
works as the front controller in Spring MVC.
34) What does @Controller annotation?
The @Controller annotation
marks the class as controller class. It is applied on the class.
35) What does @RequestMapping annotation?
The @RequestMapping annotation
maps the request with the method. It is applied on the method.
36) What does the ViewResolver class?
The View Resolver class
resolves the view component to be invoked for the request. It defines prefix
and suffix properties to resolve the view component.
37) Which ViewResolver class is widely used?
The org.springframework.web.servlet.view.InternalResourceViewResolver class
is widely used.
38) Does spring MVC provide validation support?
Yes.
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