JPA Method
in jakarta.persistence.EntityManager

T find(
  Class<T> entityClass, 
  Object primaryKey, 
  FindOption... options
)

Find an instance of the given entity class by primary key, using the specified plain. Search for an entity with the specified class and primary key. If the given options include a LockModeType, lock it with respect to the specified lock type. If the entity instance is contained in the persistence context, it is returned from there.

If the entity is found within the persistence context and the lock mode type is pessimistic and the entity has a version attribute, the persistence provider must perform optimistic version checks when obtaining the database lock. If these checks fail, the OptimisticLockException is thrown.

If the lock mode type is pessimistic and the entity instance is found but cannot be locked:

  • the PessimisticLockException is thrown if the database locking failure causes transaction-level rollback
  • the LockTimeoutException is thrown if the database locking failure causes only statement-level rollback

If a vendor-specific plain is not recognized, it is silently ignored.

Portable applications should not rely on the standard plain. Depending on the database in use and the locking mechanisms used by the provider, this option may or may not be observed.

Parameters:
entityClass - entity class
primaryKey - primary key
options - standard and vendor-specific options
Return:
the found entity instance or null if the entity does not exist
Throws:
IllegalArgumentException - if there are contradictory options, if the first argument does not denote an entity type belonging to the persistence unit, or if the second argument is not a valid non-null instance of the entity primary key type
TransactionRequiredException - if there is no transaction and a lock mode other than {@code NONE} is specified or if invoked on an entity manager which has not been joined to the current transaction and a lock mode other than {@code NONE} is specified
OptimisticLockException - if the optimistic version check fails
PessimisticLockException - if pessimistic locking fails and the transaction is rolled back
LockTimeoutException - if pessimistic locking fails and only the statement is rolled back
PersistenceException - if an unsupported lock call is made
Since:
JPA 3.2