EJB

1. Scalability

Specification requires EJB servers provide pooling both for database connections and EJB instances
Java Database Connectivity (JDBC) 2.0 standard extension is essential for scalability
The container must prevent other transactions from entering the EJB until the first transaction commits or aborts
Caching of entity EJBs is useful since they can be easily retrieved if they are requested again shortly after being returned to the pool

2. State Management

Stateless session beans are equivalent to typical COM+ components and retain no state between method calls
Stateful session beans retain state between method calls until container passivates them, such as shopping cart
An entity bean is stateful and that state persists over time
Using Container Managed Persistence (CMP) for entity beans can make state management easier
Simple entity beans will map to a single row in a single database table
Persistence Manager facilitates complex data mapping to ensure CMP entity beans are truly portable

3. Simpler Security

Based on underlying J2EE platform, which uses the security infrastructure of the underlying OS
Role-based, same as COM+
Each resource in the pool must share the same security, same as COM+

4. Fault Tolerance

Load balancing is provided by many vendors
Provided by home interface implementation
Provided by registration of factories in the Java Naming and Directory Interface (JNDI)

5. Ease of Development

Allow bean producers to concentrate on writing business logic
Declarative attributes are provided to reduce the amount of security or transaction code
An EJB producer must implement the life cycle methods, much of which can be generated by developer tools

6. Help With Deployment

An EJB-JAR (Java ARchive) file is created containing the bean, helper classes, other resources, and a deployment descriptor