What are the pros and cons of Detached objects ?

Detached objects can be passed across layers upto the presentation layer without having to use any DTOs. 

You can re-attach the detached objects to another session.

Pros

• Use in long transactions
  When long transactions are required due to user think-time, it is the best practice to break the long transaction up into two or more transactions.
  Use case

• Use detached objects from the first transaction to carry data all the way up to the presentation layer.
• These detached objects get modified outside a transaction
• Later, re-attach to a new transaction via another session

  

Cons

• Quite cumbersome to use
  Instead, re-fetch them on subsequent requests - More efficient 
• The objects hang around in Hibernate' s cache anyway.