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https://issues.apache.org/jira/browse/OPENJPA-2668?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15649120#comment-15649120
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Mark Struberg commented on OPENJPA-2668:
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I did dig deeper into our source and the spec (6.5.10 Parameter Expressions).
It seems that this behaviour might have even been intentionally. Please use
CriteriaQuery.parameter to specify parameters whose value you gonna change
later on. I verified that the resulting CriteriaQueries are perfectly reusable.
> CriteriaQuery instances should not change their state based on Query
> instances created from them
> ------------------------------------------------------------------------------------------------
>
> Key: OPENJPA-2668
> URL: https://issues.apache.org/jira/browse/OPENJPA-2668
> Project: OpenJPA
> Issue Type: Bug
> Components: jpa
> Affects Versions: 2.4.1
> Reporter: Oliver Gierke
> Assignee: Mark Struberg
>
> JPA has a two-step, programatic query creation process: first, you create a
> {{CriteriaQuery}} to build up the general query structure, add constraints on
> it etc. Then you take that instance and create a {{(Typed)Query}} instance
> from it using the currently available {{EntityManager}} and bind parameters
> to it.
> According to [reports we got for Spring Data
> JPA|https://jira.spring.io/browse/DATAJPA-969], the latter step changes the
> state of the {{CriteriaQuery}} instance, so that subsequent creations of
> {{Query}} instances from it (and subsequent parameter bindings in turn) don't
> actually get applied correctly.
> Even if the subsequent creation and parameter binding got applied, that
> change of state in {{CriteriaQuery}} instances is problematic in concurrent
> access scenarios as the bindings might override each other partially.
> Generally speaking I'd recommend to keep the {{CriteriaQuery}} instances
> immutable with regards to the creation of {{Query}} instances from them and
> the subsequent handling of those {{Query}} instances.
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