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about Entity instance lifecycle

 
vitesse wei
Ranch Hand
Posts: 100
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third question about Entity's lifecycle,give answer is D,how about B and C,can anyone explain those two statements.thanks

Which statement about an entity instance lifecycle is correct?
A. A new entity instance is an instance with a fully populated state.
B. A detached entity instance is an instance with no persistent identity.
C. A removed entity instance is NOT associated with a persistence context.
D. A managed entity instance is the instance associated with a persistence context.
 
Adam Tkaczyk
Greenhorn
Posts: 21
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A is not good because entity is in "new" state after statement
EntityClass object = new EntityClass();
so it can have no state available (no persistence identity also)

B is not good because "detached" state means that entity is no longer available in persistence context, but it was before, so it has persistence identity

C is not good because "removed" entity is still associated with persistence context because the persistence context has to make database operations to physically remove db row from database.
 
It is sorta covered in the JavaRanch Style Guide.
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