Exam 1z0-900 topic 1 question 64 discussion

Actual exam question from Oracle's 1z0-900

Question #: 64
Topic #: 1

[All 1z0-900 Questions]

A Persistence application locks entity x with a LockModeType.PESSIMISTIC_READ lock type. Which statement is true?

A. LockModeType.PESSIMISTIC_READ is the synonym of LockModeType.READ
B. This operation will force serialization among transactions attempting to read the entity data.
C. This operation will result in a TransactionRolledbackException if the lock cannot be obtained.
D. If the application updates the entity later, and the changes are flushed to the database, the lock will be converted to an exclusive look.

Show Suggested Answer

Suggested Answer: B 🗳️
Reference:
https://docs.oracle.com/javaee/7/api/javax/persistence/LockModeType.html

by emtchan at March 21, 2022, 4:29 p.m.

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maurytin

7 months, 3 weeks ago

D is the correct asnwer. JSR 338 JPA 2.1 page 95 of the specification: When an application locks an entity with LockModeType.PESSIMISTIC_READ and later updates that entity, the lock must be converted to an exclusive lock when the entity is flushed to the database[42].

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orjava

1 year, 3 months ago

Answer D. LockModeType.READ Synonymous with OPTIMISTIC. PESSIMISTIC_READ - locks the record with read lock state when you read the record. This prevents other transactions from changing the record, but still allows them to read it. PESSIMISTIC_WRITE - locks the record, preventing other transaction from reading and writing it.

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devmsaleh

2 years, 7 months ago

D is the correct answer

upvoted 2 times

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emtchan

3 years, 1 month ago

The answer should be D.