cmp-lifecycle

Entity beans (both BMP and CMP) need a well-defined lifecycle that the container manages — from creation, to ready state, to passivation, and eventual removal. If the lifecycle isn’t clearly defined, the container wouldn’t know when to call ejbLoad(), ejbStore(), or when to create/remove bean instances.

The CMP entity bean lifecycle is identical to the BMP lifecycle (Figure 8.4 matches Figure 7.3). The only addition is the ejbSelect() method which can run in both Pooled and Ready states. All callback methods (ejbLoad, ejbStore, ejbCreate, etc.) are empty in CMP because the container handles everything.

1. Container instantiates bean via newInstance() → enters Pool state
2. Client calls create() or find() → container calls ejbCreate() / ejbActivate() → enters Ready state
3. In Ready state: ejbLoad() (container loads data), business methods run, ejbStore() (container saves data)
4. Bean can return to Pool via ejbPassivate() (released back to pool)
5. From Pool: ejbRemove() → bean destroyed, or ejbSelect() can run in Pool state (for home methods)
6. The key difference from BMP: all callbacks are empty — container does the actual database work automatically

• Identical to BMP lifecycle — no structural differences
• ejbSelect() is the only method that can run in Pool state (for home methods)
• All lifecycle callbacks are empty in CMP — container handles persistence automatically
• Container manages when to call ejbLoad() and ejbStore() based on transaction boundaries
• Passivation only applies to stateful session beans, not entity beans (entity beans stay in Ready or Pool)

• Built from: Entity Bean — lifecycle applies to all entity beans
• Built from: Stateful Lifecycle — similar pool/ready concept but for session beans
• Contrasts with: Stateless Lifecycle — stateless has no passivation, only method-ready pool
• Related: CMP Abstract Accessors — callbacks are empty because container uses abstract methods
• Related: Instance Pooling — pooled state is where beans wait for work

• Despite the lifecycle diagram showing ejbCreate in the flow, CMP’s ejbCreate is empty — container does the INSERT
• ejbSelect() running in Pool state is a subtle detail often missed in exams
• Entity beans don’t passivate like stateful session beans — they go to Pool, not Passive state
• The lifecycle is the same for CMP and BMP, but the implementation of callbacks differs completely