There is a Puzzled question.
I written a class User like this:

@Entity
@Table(name = "user")
public class User {
private String name;
private int id;
private String message;
public User() { }
public User(String name, String message) {
this.name = name;
this.message = message;
}
@Id
@GeneratedValue
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}

and I written a Manager class like this:

@PersistenceContext
EntityManager em;
......
User user = new User(name, message);
em.persist(user);
.....

When the JBoss Server is running,everything is OK.
the application create a new table named "user",and add data into the table.But after I close Server, I found everything is lost."user" table cannot
de find,and data is yet!!!
what happend?