Raj Jindal

How can we rollback a distributed transaction in java. If we are using CMP or BMP EJB, is there anyway to rollback the transaction that is deployed on distributed servers.

That's fine that the container will return the collection of primary keys correspondingto the SQL query. What will be the internal representation of records in the memory. When i need some record Will i need to use ejbFind() method again.

I have an entity bean mapped to a database table. There are 1000 records in the database table. If i select all the records using SELECT * FROM TABLE. How many instances of the entity bean will exist ? Will there be 1000 instances of the entity bean in memory ? I just want to know what will be the representaion of the records in memory for my Query ?

Thanks...!!!

Yes guys, I am talking about bean Managed Persistence (BMP) mapping to a table with duplicate records or without primary key

Is it possible to develop a BMP for a database table having no primary key field.

Suppose I have a table without any primary key (i.e table has duplicate records). Now i want to develop a BMP that will manipulate this table.
It is said that an entity bean represents a unique record in some persistence database table. So how will it associate the entity bean EjbOject with a unique record in databse since table has duplicate records.
What is the purpose of primary key class in this case ?
Is primary key required or not ?
How is it possible to handle such type of situation with Entity beans.
Thanks in advance.

I have a set of libraries in C.I want to use these C libraries from a java program that will transfer files over the internet.
I just want to know that what are the implications of JNI in this context. Will it hamper the speed. Also security issues, If any.
Thanks in advance

It is said that struts is an implementation of MVC. But can anybody tell me that how struts is superior to MVC. why struts is so famous. what are the faclities it provide over MVC.

How many initialContexts are tehre in websphere ?
I know that there are two. One is Local and another one is Remote ? Can anybody explain in detail the difference between the two.
when are they most appropriate to use

What is the alternative to Entity bean. In other words, Is thre any other component that can provide persistence or the same facilities as that of Entity bean.

can we implement threads in ejb bean.
If yes, what is the benefit of this.

can we perform any I/O operation or file reading in some method of an EJB ban class.
Is it the right approach or some other good alternative is there

In my EJB bean, I am executing a sequence of sql statements in block. ie in same transaction. If any of the SQL gets failed, the exception will occur.
1. How can i rollback the transaction.
2. On rollback, If i want to perform some function, where will i be writing the logic for that.
e.g:- when exception occurs, control goes to catch bloc. should i write rollback in catch block. If yes, should i also write the logic to perform something extra operation on rollback, also in catch block.

what is the difference between EJBException and RemoteException ?
where and how are these exceptions catched by the EJB ?

Servlet specification says that Only a single instance of a servlet is created by the Container at startup time. If more than one user calls that servlet, an additional thread is created to serve the request.
I just want to know that Can we limit the number of threads ? In other words If one lakh (100,000 users) access the servlet at the same time. Will one lakh threads be created.
where can we specify that servlet engine can't create threads beyond a specified limit, If possible.
If no, where can we specify to limit the number of threads ?
Thanks in advance