JPA Method
in javax.persistence.EntityManager

T find(
  Class<T> entityClass, 
  Object primaryKey
)


Find by primary key. Search for an entity of the specified class and primary key. If the entity instance is contained in the persistence context, it is returned from there.
Parameters:
entityClass - entity class
primaryKey - primary key
Return:
the found entity instance or null if the entity does not exist
Throws:
IllegalArgumentException - if the first argument does not denote an entity type or the second argument is is not a valid type for that entity's primary key or is null
Since:
JPA 1.0