EJB 3.0 Entity Bean

[Ajan Raj]

Can anyone tell me the steps to create EJB 3.0 Entity Bean in Eclipse 3.3.2 with JBoss Applicaion server. I had created a sample Application but while lookup its throwing error such as javax.naming.NameNotFoundException: EntityBean not bound

[Jaikiran Pai]

"Aj an"

Please click the "My Private Messages" link (at the top of this page) for a message from JavaRanch.

[Ajan Raj]

Jaikiran Pai wrote:"Aj an"

Please click the "My Private Messages" link (at the top of this page) for a message from JavaRanch.

Hey i don't understand what you are expecting me to do. Eventhough i had changed the name you are sending the same message.

[Jaikiran Pai]

Ajan Raj wrote:

Eventhough i had changed the name you are sending the same message.

I sent it only once, before you changed your display name.

[Peter Johnson]

Could you post the source for your entity bean? And the code that is using it, which I assume is the code that is getting the NameNotFoundException. Don't forget to wrap the code in 'code' tags.

[Ajan Raj]

Peter Johnson wrote:Could you post the source for your entity bean? And the code that is using it, which I assume is the code that is getting the NameNotFoundException. Don't forget to wrap the code in 'code' tags.

I am new to EJB. I had download a sample example and work on that.

In the servlet i am Using

InitialContext ctx = new InitialContext();
System.out.println("Get initial context");
hello = (BookRemote) ctx.lookup("BookBean/remote");

These are the files which i am using in the ejb.
Book.java
BookBean.java
BookLocal.java
BookRemote.java.

And herewith i have given the code.

BookLocal.java

package example;
import javax.ejb.Local;

@Local
public interface BookLocal {
public void test();

}

BookRemote

package example;
import javax.ejb.Remote;

@Remote
public interface BookRemote {
public void test();

}

BookBean.java

package example;
import java.util.Iterator;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

public class BookBean implements BookLocal, BookRemote {
@PersistenceContext
EntityManager em;
public static final String RemoteJNDIName = BookBean.class.getSimpleName() + "/remote";

public static final String LocalJNDIName = BookBean.class.getSimpleName() + "/local";

public void test() {
// TODO Auto-generated method stub
System.out.println("Enter into Bean class");
// TODO Auto-generated method stub
Book book = new Book(null, "My first bean book", "Sebastian");
em.persist(book);
Book book2 = new Book(null, "another book", "Paul");
em.persist(book2);
Book book3 = new Book(null, "EJB 3 developer guide, comes soon",
"Sebastian");
em.persist(book3);

System.out.println("list some books");
List someBooks = em.createQuery("from Book b where b.author=:name")
.setParameter("name", "Sebastian").getResultList();
for (Iterator iter = someBooks.iterator(); iter.hasNext();)
{
Book element = (Book) iter.next();
System.out.println(element);
}
System.out.println("List all books");
List allBooks = em.createQuery("from Book").getResultList();
for (Iterator iter = allBooks.iterator(); iter.hasNext();)
{
Book element = (Book) iter.next();
System.out.println(element);
}
System.out.println("delete a book");
em.remove(book2);
System.out.println("List all books");
allBooks = em.createQuery("from Book").getResultList();
for (Iterator iter = allBooks.iterator(); iter.hasNext();)
{
Book element = (Book) iter.next();
System.out.println(element);
}

}

}

Book.java

package example;

import java.io.Serializable;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;
import javax.persistence.TableGenerator;

@Entity
@Table(name="book")
@SequenceGenerator(name = "book_sequence", sequenceName = "book_id_seq")
@TableGenerator(name="book_id", table="primary_keys", pkColumnName="key", pkColumnValue="book",
valueColumnName="value")
public class Book implements Serializable {

private static final long serialVersionUID = 7422574264557894633L;
private Integer id;
private String title;
private String author;

public Book() {
super();
}

public Book(Integer id, String title, String author) {
super();
this.id = id;
this.title = title;
this.author = author;
}

@Override
public String toString() {
System.out.println("Get the Author,title etc.. from Book Class");
return "Book: " + getId() + " Title " + getTitle() + " Author "
+ getAuthor();
}

public String getAuthor() {
return author;
}

public void setAuthor(String author) {
this.author = author;
}

@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "book_sequence")
public Integer getId() {
return id;
}

public void setId(Integer id) {
this.id = id;
}

public String getTitle() {
return title;
}

public void setTitle(String title) {
this.title = title;
}
}

Can you help me out from this problem

[Jaikiran Pai]

...
import javax.persistence.PersistenceContext;
...

public class BookBean implements BookLocal, BookRemote {

This one is missing the @Stateless annotation. Hence its not considered a bean.

Add this:

...
import javax.ejb.Stateless;
...
@Stateless
 public class BookBean implements BookLocal, BookRemote { 
...

[Ajan Raj]

Thanks a lot jaikiran. It works fine. Can you please tell me the site to get EJB 3.0 tutorial. By google search i am getting a lot. But i want to know from the basic. Can you suggest me the site.

Jaikiran Pai wrote:

...
import javax.persistence.PersistenceContext;
...

public class BookBean implements BookLocal, BookRemote {

This one is missing the @Stateless annotation. Hence its not considered a bean.

Add this:

...
import javax.ejb.Stateless;
...
@Stateless
 public class BookBean implements BookLocal, BookRemote { 
...

[Jaikiran Pai]

EJB3.0 tutorial for JBossAS5 is here. For AS4.x, its here