What part of the J2EE platform handles data storage and retrieval on behalf of a container-managed entity bean?
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The thin client.
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Deployment descriptors.
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The JAR file.
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The bean's container
In container-managed persistence, the EJB container automatically handles all database operations - INSERT, UPDATE, DELETE, and SELECT. The container generates the SQL code and manages the connection pooling, transactions, and caching. The thin client (A) is the user interface, not involved in persistence. Deployment descriptors (B) configure behavior but don't execute data operations. The JAR file (C) is just packaging.
In J2EE, container-managed persistence (CMP) entity beans delegate all data storage and retrieval logic to the EJB container itself — the container automatically generates the SQL (or other persistence-layer code) to load and save the bean's state, so 'the bean's container' is correct. The thin client is just the presentation-tier consumer and has no persistence role. Deployment descriptors only configure metadata (mappings, transaction attributes) — they don't perform storage operations themselves. The JAR file is merely a packaging artifact for deployment, not an active runtime component that handles data access.