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Professional EJB, Chapter 5 Quiz

By Dan O'Connor
December 2001

This short quiz is based on Professional EJB: Chapter 5, "The EJB 2.0 Entity Model." Test your knowledge of local interfaces, container-managed persistence, and the Enterprise JavaBean (EJB) 2.0 spec.

Choose one answer for each question, then click Submit to see how you scored.

1. A local home or component interface for an EJB can only be used by:

A.	Another EJB
B.	A web-tier client
C.	A business logic-tier client
D.	A client located in the same Java^TM Virtual Machine (JVM)¹

2. Local interfaces have declarative:

A.	Transactions and security
B.	Transactions only
C.	Security only
D.	Neither, for performance reasons

3. An entity in a unidirectional relationship that is the target of a role with a cmr field:

A.	Must have local home and component interfaces
B.	Must have remote home and compnent interfaces
C.	May have either local or remote interfaces, but not both
D.	May have any combination of local or remote interfaces

4. An entity in a unidirectional relationship that is the source of a role with a cmr field:

A.	Must have local home and component interfaces
B.	Must have remote home and compnent interfaces
C.	May have either local or remote interfaces, but not both
D.	May have any combination of local or remote interfaces

5. The bean class for an entity that uses the EJB 2.0 model of container-managed persistence:

A.	Must implement `java.io.Serializable`
B.	Is only used for better integration with popular IDEs
C.	Must be abstract
D.	Must not be abstract

6. The legal collection class type(s) to represent a many-valued relationship are:

A.	`java.util.Collection` only
B.	`java.util.Collection` and `java.util.Set`
C.	`java.util.List, java.util.Set`, and `java.util.Map`
D.	`java.util.Map` only

7. If you call a "set" abstract accessor for a cmr field, it can:

A.	Throw a `java.sql.SQLException`
B.	Automatically cascade delete an entity
C.	Automatically change the value of `cmr` fields in up to three additional beans
D.	You can never call an abstract accessor

8. You can only specify cascade-delete on a relationship role if:

A.	The role has a multiplicity of 'One'
B.	The other role in the relationship has a multiplicity of 'One'
C.	The role has a multiplicity of 'Many'
D.	The other role in the relationship does not already use cascade-delete

9. If an entity has a relationship to another entity, it must:

A.	Declare that entity reference in the deployment descriptor using the `<ejb-ref>` element
B.	Declare that entity reference in the deployment descriptor using the `<ejb-local-ref>` element
C.	Declare that entity reference in the deployment descriptor using the `<ejb-link>` element
D.	No entity reference declaration is required

10. The bean developer must be cautious when iterating over a relationship collection class, because:

A.	Concurrent transactions can modify the values
B.	Changes to its contents can violate foreign key constraints in the database
C.	Changes to its contents can trigger a referential integrity change to the collection class itself
D.	The container developer is not required to support the Iterator class's `next` method

11. The EJB 2.0 specification introduces ejbSelect methods. These are:

A.	Abstract methods in the bean class that call a query
B.	The local home interface equivalent of a finder method
C.	Methods in the component interface that call a query
D.	A method that allows the bean developer to choose between a local and remote interface

12. The new EJB Query Language (EJB-QL) has three clauses: select, from, and where. Of these:

A.	Only the from clause is mandatory
B.	Only the select and from clauses are mandatory
C.	Only the where clause is mandatory.
D.	All clauses are mandatory.

13. In EJB-QL, date and time literals are represented by:

A.	A string in the format `MM-DD-YYYY HH:MM:SS +MILLISECONDS`
B.	A string in a locale-determined format
C.	A string in a vendor specific format
D.	A long value that represents a millisecond count, such as `979837813000`

14. The type of interface (local or remote) returned from an ejbSelect statement can be:

A.	Specified in the query
B.	Specified in the deployment descriptor
C.	Specified by the client
D.	Is always a local interface

15. The functions available for use in the where clause of an EJB-QL query are:

A.	All functions defined in standard SQL
B.	All functions defined by the target database
C.	All functions with defined escapes in JDBC 2.0
D.	A limited subset of the functions defined for JDBC 2.0

¹ As used on this web site, the terms "Java virtual machine" or "JVM" mean a virtual machine for the Java platform.


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