EJB Questions et reponses d'entretien
Question : Static variables in EJB should not be relied upon as they may break in clusters.Why?Reponse : Static variables are only ok if they are final. If they are not final, they will break the cluster. What that means is that if you cluster your application server (spread it across several machines) each part of the cluster will run in its own JVM.Say a method on the EJB is invoked on cluster 1 (we will have two clusters - 1 and 2) that causes value of the static variable to be increased to 101. On the subsequent call to the same EJB from the same client, a cluster 2 may be invoked to handle the request. A value of the static variable in cluster 2 is still 100 because it was not increased yet and therefore your application ceases to be consistent. Therefore, static non-final variables are strongly discouraged in EJBs. |
Enregistrer pour revision
Ajoutez cet element aux favoris, marquez-le comme difficile ou placez-le dans un ensemble de revision.
Connectez-vous pour enregistrer des favoris, des questions difficiles et des ensembles de revision.
Est-ce utile ? Oui Non
Les plus utiles selon les utilisateurs :
- What are the different kinds of enterprise beans?
- What is Entity Bean?
- What is Session Bean?
- What is the difference between Container-Managed Persistent (CMP) bean and Bean-Managed Persistent(BMP)?
- What are the methods of Entity Bean?