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What is the difference between Stateful session bean and Stateless session bean
Answer posted by Mohan on 2005-05-20 08:45:36: Stateful session beans have the passivated and Active state which the Stateless bean does not have.
srikanthm2
- Jan 28th, 2008
Stateful session beans follow the instance passivation techniqueStateless session beans follow the instance pooling technique.ejbActivate() and ejbPassivate() methods are not called in Stateless session beansI
Jeevan Sunkersett
- Jul 16th, 2007
Stateful Session Bean (SFSB) do not have the concept of pooling
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What is deployment descriptor
Answered by Jey on 2005-05-08 12:59:41: Deployment Descriptor is a XML document with .xml extenion. It basically descripes the deployment settings of an application or module or the component. At runtime J2EE server reads the deployment descriptor and understands it and then acts upon the component or module based the information mentioned in descriptor. For example EJB module has a deployment...
kirankpv
- Feb 9th, 2008
Deployment Descriptor is a XML document with .xml extenion. It basically describes the deployment settings of an application . At runtime webcontainer reads the deployment descriptor and understa...
Jey
- May 8th, 2005
Deployment Descriptor is a XML document with .xml extenion. It basically descripes the deployment settings of an application or module or the component. At runtime J2EE server reads the deployment des...
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Entity bean is an abstract class and its local and home interfaces also extends an abstact class. So how can we instantiate home or local interface?
jettyprakash
- Mar 8th, 2008
Clients never dealt with direct instances of Entity Bean. It deals with container implementations of home and component interface (stubs & skeletons - aka deployement code)It is the container responsibility to Wrap a class around the abstract definition of Entity bean.
jayanandan
- Jan 14th, 2008
it is upto container which instantitates and maintain all entity bean in the ejb container.But to act like a entity bean,the developer has to implement EntityBean and all abstract methods defined in i...
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PortableRemoteObject.narrow()
What is the purpose of the call to PortableRemoteObject.narrow()?
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JNDI
Why is JNDI used.Do we have any alternative for JNDI?
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What kind of bean(entity/session) will you use if there are no database transactions and all you use is a read-only database.
coolguy_krkr
- May 11th, 2008
If you have no database transactions and you need just data fetch..I would not go for both of them..We can as well use simple dao with jdbc call to fetch data. If you have to pick one from the beans then definetely it would be stateless for this scenario.
s_s78
- May 3rd, 2006
If u are only reading the database then u dont need to use Entity been at all.Entity been slows down data fetch operation.U just need to use stateless session bean.
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What is the default transaction attribute in transactions
harish.verma
- Mar 6th, 2007
The default choice for a transaction attribute is Required. Using this attribute ensures that the methods of an enterprise bean are invoked within a JTA transaction. In addition, enterprise beans with...
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What is the difference b/w EJB2.1 and EJB3.0?
saankhya2003
- Jul 29th, 2008
The main difference lies in the persistence, In case of EJB 3.0 there?is JPA, Java persistence API which makes the mapping of EntityBeans with the database easy, with the help of a service called as ...
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Is it necessary to create instance of the bean for each and every request?
vinaykurudi
- Aug 13th, 2008
No, why because beans are maintaining?one bean pool. If any request comes to that bean it will first see in that pool if any instance is free, then that instance will be thrown to the request. If no ...
rogesh
- Jan 19th, 2006
I think 238 instances will created for one bean
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How many clients can share a same instance of a stateful session bean?
muktasharad
- Sep 7th, 2008
Number of clients can share the same instance of above mentioned bean because in stateful session bean multiple clients are assigned with one instance only, so they would all share taht instance.thank you!
NIRAJ KUMAR
- Oct 20th, 2006
Hello Friends, Only one client can share a same instance of a stateful session bean.As the name suggested that stateful session beans maintained the session information of the client so only one client can share the same instance of a stateful session bean.
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Map Entity Bean Field with Oracle
How to map the Entity Bean field with Oracle?
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Have you faced Any problems while deploying ejb's in weblogic
what are the serious problems you had faced while using EJB's
alapatibk
- Nov 11th, 2008
Just deploying the jar file will not help in Weblogic, you need to compile the ejb source using the ejb compiler "ejbc" supplied by weblogic.Otherwise we will see version miss match errors and it will not be deployed.I forgot the exact error number.
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Jarfiles to be build in EJB 2.0
Which are the jar files that need to be externally added to run a simple java program that accesses a session bean in EJB 2.0, using Jboss 4.X application server.
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What are the call back methods in Session bean
Answered by Jey on 2005-05-08 19:41:22: Session bean callback methods differ whether it is Stateless or stateful Session bean. Here they are. Stateless Session Bean 1. setSessionContext() 2. ejbCreate() 3. ejbRemove() Stateful Session Bean 1. setSessionContext() 2.ejbCreate() 3.ejbPassivate() 4.ejbActivate() 5.ejbRemove()
ganeshjava
- Nov 26th, 2008
Please note down that ejbCreate() is not a method of Session Bean, for reference see the link?http://java.sun.com/j2ee/sdk_1.3/techdocs/api/javax/ejb/SessionBean . html
Satish
- May 30th, 2007
Session callback methods setSessionContext();unsetSessionContext();ejbLoad();ejbActivate();ejbPassivate();ejbRemove();Entity bean call back methodspublic void setEntityContext(javax.ejb.EntityContext ...
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How do you throw EJB/SQL exceptions to front-end/presentation layer ?
raju.k
- May 4th, 2009
In the JSP page we?specify an error page for that exception and forward the control to the specified error page when?an exception comes and we can display the exception in a good manner.
santanu_nandi
- Mar 9th, 2008
Inside the EJB code you put a try catch block. Inside the catch block you throw new EJBException. In the method signature also you declare that the method will thow the exception and not handle it.At ...
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What is the difference between ejbstore and ejbload?
AkshataShriyan
- Jul 3rd, 2009
They are call back methods.They are used to notify ejb beans of the state.Called at the boundaries of the transaction.Whenever tx.begin(), ejbload() is called to notify beans of data being refreshedWhenever tx.commit, ejbstore() is called to notify beans that data is being persisted
VenkitaKrishnan
- Apr 20th, 2009
These 2 callback methods are avaliable in the EntityBean Interface and will be used by the container to load the data from the Database into the Bean (ejbLoad) and from the bean to the Database (ejbSt...
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What is session facade
bhushanamca
- Jul 7th, 2009
Session Facade is a design pattern. It is used to reduce the network round trips between client and EJB comp. SLSB comp will act as session facade and it is receiving request from client and communic...
coolguy_krkr
- May 11th, 2008
Session facade is one design pattern that is often used while developing enterprise applications.It is implemented as a higher level component (i.e.: Session EJB), and it contains all the iteractions ...
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When you will chose CMP and BMP
geeksterrahul
- Jul 23rd, 2009
CMP gets complex when the query involves two or more tables. In such case you might want to go for a BMP.BMP is a good choice when the task involves two or more tables.CMP does not have support for certain JDBC CICS. In such case BMP is a good choice.
gskumar
- Sep 12th, 2005
When ever you want to use SAP or any ERP concept for ur back end then it is better to go for BMP's .If u are very particular about the performance of application then better use BMP rather than using CMP.
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BLOB & CLOB
What is the expansion for BLOB & CLOB?
myogeshchavan97
- Jul 31st, 2009
Blob Stands for Binary Large Object.Clob Stands for Character Large Object.
itsvenuhere
- Jul 28th, 2009
BLOB: Binmary Large ObjectCLOB: Character Large ObjectBoth of these are used to store large amounts of data.
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