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AdamBien/47thAirhacksQ&A.md

Created January 10, 2018 08:18
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vanuatoo commented Feb 5, 2018

What is your approach to this scenario:

There is an Entity with columns: ID and Name. Name is annotated as @column(unique = true)

There is a REST Resource which injects session bean.
POST Request is sent to REST Resource which invokes business method in a session bean.
In a session bean there is a line: em.persist(bean);

The goal is to throw business exception from the session bean when Constraint Violation happens in the database but the exception is not thrown unless you put em.flush(); after em.persist();

Is putting em.flush() a correct approach?
Another approach would be to first find an object with the same Name, but there is still a chance Constraint Violation happens in a race condition.

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