Srinivas Jadcharla

• Jul 18th, 2005

Yes

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JavaPerson

• Jul 21st, 2005

Decorator is not a EJB Design pattern. It is a Java pattern.

sai

• Apr 28th, 2005

No

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To have a consistent interface, so that there is no different interface that you need to implement for Stateful Session Bean and Stateless Session Bean. Both Stateless and Stateful Session Bean implement javax.ejb.SessionBean and this would not be possible if stateless session bean is to remove ejbActivate and ejbPassivate from the interface. You could argue that the two (stateful and stateless) are...

Ginni

• Jul 21st, 2005

The simple reason is to manage your resources. For eg. if you use/open any third party resource on ejbActivate, you need to make sure ejbPassivate close the connection/ release the use of resource regardless of stateful session or stateless session.

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Ginni

• Jul 21st, 2005

Yes, you can create entity bean without impelementing the create() method. The ejbs will be instantiated by findByPK or any finder methods.

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Amitav C

• Jul 21st, 2005

Its actual implementation is done by the Container.

RajeshRokkam

• Jun 3rd, 2005

We have to provide abstract data to object mapping that maps the fields in our bean to a batabase, and abstract methods methods that corelate these fields.

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Answer posted by Mohan on 2005-05-21 19:24:23: All Beans support Instance Pooling

Vj

• Jul 22nd, 2005

EJB does indeed support the effect of pooling stateful session beans.Only a few instances can be in memory when there are actually many clients. But this pooling effect does not come for free---the pa...

raj

• Jul 4th, 2005

Statefull session bean does not maintain instance pooling, stateless session beans and entity beans can maintain instance pooling

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Answered by Jey on 2005-05-08 11:06:46: When the EJB container needs to synchronize the instance variables of an entity bean with the corresponding values stored in a database, it invokes the ejbLoad and  ejbStore methods. The ejbLoad method refreshes the instance variables from the database, and the ejbStore method writes the variables to the database. The client cannot call ejbLoad...

Vj

• Jul 22nd, 2005

Note: ejbLoad and ejbStore methods are to be coded only if you are creating a BMP. For CMP these methods are handled by the container.

Sanjay Guha

• May 25th, 2005

ejbLoad method: This method is called when it is necessary to synchronize the bean with data from the database. This will most likely trigger a SELECT to occur. The ejbLoad is triggered when the ...

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pradeep.gt

• Jul 24th, 2005

1. doesnot exsist 2. exsists 3. passivate  invoke ejbcreate() set the sessioncontext() call create()  if the session idle call ejbPassivate() to get back t...

John

• May 3rd, 2005

a Stateful Session Bean has three states. Does not exists, Method Ready and Passivated states.  Like Stateless beans, when the Stateful Session Bean hasnt been instantiated yet (so it is not...

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pradeep

• Jul 24th, 2005

1. dose not exsist 2. exsist  to start the session set the sessionContext() call create()  to end session call remove

Kiran

• May 3rd, 2005

stateless session bean has only two states: Does Not Exists and Method Ready Pool.  A bean has not yet instantiated (so it is not an instance in memory) when it is in the Does Not Exists st...

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khan

• Jul 29th, 2005

According to EJB 2.1 specificationThe EJB QL consists of 4 clauses: SELECT, FROM(mandatory) WHERE and ORDER BY(optional).

Srinivas Jadcharla

• Jul 18th, 2005

The EJB QL query string consists of three clauses: SELECT, FROM, and WHERE.WHERE is optional.

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sri

• Aug 4th, 2005

We can call java beans by using jsp:useBean tag

Manoj Singh

• Jul 25th, 2005

Yes We can call java beans in Java

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Sumit Kumar

• Aug 30th, 2005

A Bean persists by having its properties, fields, and state information saved and restored to and from storage. The mechanism that makes persistence possible is called serialization. When a Bean insta...

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Partha Mandal

• Sep 14th, 2005

Interface is mainly used to seperate the server side business logic from the client. Because interface contains only the method defination which is getting exposed to the client. Hence if one modifies...

Manoj Singh

• Jul 25th, 2005

The Main use of interface in java is to implements the concept of Multiple Inheritence.

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Saket

• Sep 14th, 2005

Its possible to map more than one tables to a CMP. Have a look athttp://e-docs.bea.com/wls/docs81/faq/ejb.html#260273

Srinivas Jadcharla

• Jul 18th, 2005

No

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Ravi Dalal

• Sep 19th, 2005

stateful beans maintains their state through instance variables. the values of the instance variables is specific to client. when the bean instance needs to be removed from the pool (usually LRU repla...

Srinivas Jadcharla

• Jul 18th, 2005

A stateful session bean is an enterprise bean (EJB component) that acts as a server-side extension of the client that uses it. The stateful session bean is created by a client and will work for only t...

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Rajnish Sasmal

• Sep 27th, 2005

You can use two methods like insertRow() and deleteRow() of ejbCreate() for insert and delete the data from the data base in entity Bean.

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Answered by Nikhil on 2005-05-11 11:28:14: Lazy loading is a characteristic of an application when the actual loading and instantiation of a class is delayed until the point just before the instance is actually used. The goal is to only dedicate memory resources when necessary by only loading and instantiating an object at the point when it is absolutely needed.  Tools such as Eclipse have...

catura_ashish

 Profile Answers by catura_ashish Questions by catura_ashish

• Oct 6th, 2005

In Lazy loading, you load the child data as and when required.Example:public class OrderBean implements EntityBean {        private long orderId;   &n...

Nikhil

• May 11th, 2005

Lazy loading is a characteristic of an application when the actual loading and instantiation of a class is delayed until the point just before the instance is actually used. The goal is to only dedica...

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Answered by Jey on 2005-05-08 12:51:03: EJB 2.0 adds the local beans, which are accessible only from within the JVM where beans are running in.  In EJB 1.1, we had to implement remote client views for all these beans, even if we had no remote clients.

suman medisetti

• Oct 10th, 2005

EJB 2.0 came with new features which not available in EJB1.1 they are auto primarykey generation,EJB-query language,local interfaces,relationships.

Srinivas Jadcharla

• Jul 17th, 2005

some more features along with Local beans    1.message driven beans  2.Support for EJB Query language    3.New CMP Model. It is based on a new contract called the abstract per...

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Answer posted by Mohan on 2005-05-20 08:44:39: SessionBeans typically are used to represent a client they are of two typse  Stateful Session Beans : they maintain conversational state between subsequest calls by a client  Stateless Session Bean : consider this as a servlet equivalent in EJB. It is just used to service clients regardless of state and does not maintain any state....

Balakrishnan

• Oct 17th, 2005

Session bean is encapsulates the business logic. and carry out the task for behalf of the client. It have two types.one is stateful session bean. this is maintain the convesional state.another one is stateless session bean. donot maintain the conversional.state.

Chandana Ekanayake

• Oct 14th, 2005

 Ok,If you want to find the inverse of a Matrix then We can use session been encapsulated the logic of finding inverse of a matrix, is an example for stateless session been.&n...

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John

• May 3rd, 2005

We can describe the following common rules for choosing whether to use remote client view or local client view:  When you will potentially use a distributed environment (if your enterprise b...

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