The following guidelines can improve performance of EJB components. Keep in mind that decomposing an application into many EJB components creates overhead and can degrade performance. EJB components are not simply Java objects. They are components with semantics for remote call interfaces, security, and transactions, as well as properties and methods.
Use high-performance beans as much as possible to improve the overall performance of your application. For more information, see Tuning Tips for Specific Types of EJB Components
Stateless Session Beans and Message Driven Beans
Stateful Session Beans
Container Managed Persistence (CMP) entity beans configured as read-only
Bean Managed Persistence (BMP) entity beans configured as read-only
Caching can greatly improve performance when used wisely. For example:
Cache EJB references: To avoid a JNDI lookup for every request, cache EJB references in servlets.
Cache home interfaces: Since repeated lookups to a home interface can be expensive, cache references to EJBHomes in the init() methods of servlets.
Cache EJB resources: Use setSessionContext() or ejbCreate() to cache bean resources. This is again an example of using bean lifecycle methods to perform application actions only once where possible. Remember to release acquired resources in the ejbRemove() method.
The stub classes needed by EJB applications are generated dynamically at runtime when an EJB client needs them. This means that it is not necessary to generate the stubs or retrieve the client JAR file when deploying an application with remote EJB components. When deploying an application, it is no longer necessary to specify the --retrieve option, which can speed up deployment.
If you have a legacy rich-client application that directly uses the CosNaming service (not a recommended configuration), then you must generate the stubs for your application explicitly using RMIC. For more information, see Sun Java System Application Server 9.1 Troubleshooting Guidefor more details.
Removing unneeded stateful session beans avoids passivating them, which requires disk operations.
Follow these tips when using the EJB cache and pools to improve performance:
Explicitly call remove(): Allow stateful session EJB components to be removed from the container cache by explicitly calling of the remove() method in the client.
Tune the entity EJB component’s pool size: Entity Beans use both the EJB pool and cache settings. Tune the entity EJB component’s pool size to minimize the creation and destruction of beans. Populating the pool with a non-zero steady size before hand is useful for getting better response for initial requests.
Cache bean-specific resources: Use the setEntityContext() method to cache bean specific resources and release them using the unSetEntityContext() method.
Load related data efficiently for container-managed relationships (CMRs). For more information, see Pre-fetching Container Managed Relationship (CMR) Beans
Identify read-only beans: Configure read-only entity beans for read only operations. For more information, see Read-Only Entity Beans