# Projections Failing - Instantiation Exception

**URL:** <https://discourse.hibernate.org/t/projections-failing-instantiation-exception/12224>\
**Category:** Hibernate ORM\
**Created:** [April 24, 2026, 5:58am UTC](https://discourse.hibernate.org/t/projections-failing-instantiation-exception/12224 "2026-04-24T05:58:59Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![gmatege](https://avatars.discourse-cdn.com/v4/letter/g/74df32/32.png) [@gmatege](https://discourse.hibernate.org/u/gmatege)\
**Post date:** [April 24, 2026, 5:58am UTC](https://discourse.hibernate.org/t/projections-failing-instantiation-exception/12224/1 "2026-04-24T05:58:59Z")

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Upgrading from 7.2.0.Final to 7.3.1.Final causes org.hibernate.InstantiationException: Cannot instantiate query result type, found no matching constructor

Problem is in class RowTransformerConstructorImpl Line: 46

This was once a problem in early version 6, And was fixed BUT It seems merging just brought it back - Anyway, Thing is - When one projects, The results are not expected to be loaded into an entity object (hence looking for a suitable constructor is not necessary), And remember in new implementation we already have configured Tuple Transformers…

As pointed out, It once appeared as indicated here:

> [@Projection fails with InstantiationException after Hibernate 6 migration](https://discourse.hibernate.org/t/projection-fails-with-instantiationexception-after-hibernate-6-migration/10375):
>
> After the migration to Quarkus 3.14 and Hibernate 6, custom query projections stopped working. I have many more examples but all comes to this exception and combination of a custom query and an aggregate class projection. The exception I get: org.hibernate.InstantiationException: Cannot instantiate query result type 'xx.domain.UnitDetails' due to: xx.domain.BusinessUnitDetails.\<init\>(java.lang.String,xx.domain.BusinessUnitType,java.lang.Integer) at org.hibernate.sql.results.internal.Row…

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**Author:** ![beikov](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.hibernate.org/beikov/32/258_2.png) [@beikov](https://discourse.hibernate.org/u/beikov)\
**Post date:** [April 27, 2026, 3:05pm UTC](https://discourse.hibernate.org/t/projections-failing-instantiation-exception/12224/2 "2026-04-27T15:05:02Z")

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Please try to create a reproducer with our [test case template](https://github.com/hibernate/hibernate-test-case-templates/blob/master/orm/hibernate-orm-7/src/test/java/org/hibernate/bugs/JPAUnitTestCase.java) and if you are able to reproduce the issue, create a bug ticket in our [issue tracker](https://hibernate.atlassian.net) and attach that reproducer.

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**Author:** ![gmatege](https://avatars.discourse-cdn.com/v4/letter/g/74df32/32.png) [@gmatege](https://discourse.hibernate.org/u/gmatege)\
**Post date:** [May 29, 2026, 2:33am UTC](https://discourse.hibernate.org/t/projections-failing-instantiation-exception/12224/3 "2026-05-29T02:33:33Z")

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Hi,

Just to give an update on this bug, Its still present in the latest Hibernate 7.4.0.Final - Haven’t found time to create a reproducer, But I personally believe its self-explanatory - Try projecting properties of an entity, It should come right up…

Exception in thread “taskExecutor-1” org.hibernate.InstantiationException: Cannot instantiate query result type, found no matching constructor ‘SomeEntity’  
at org.hibernate.sql.results.internal.RowTransformerConstructorImpl.(RowTransformerConstructorImpl.java:46)

Its looking for a constructor on the entity for a projection, Anyways we had to revert back to version 7.3.0.Final, Thats the last version without this bug…

Thanks.

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<div class="post-metadata">

**Author:** ![beikov](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.hibernate.org/beikov/32/258_2.png) [@beikov](https://discourse.hibernate.org/u/beikov)\
**Post date:** [May 29, 2026, 8:53am UTC](https://discourse.hibernate.org/t/projections-failing-instantiation-exception/12224/4 "2026-05-29T08:53:39Z")

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It might be a surprise to you, but we have tests that cover projections, so we really need a reproducer if you want us to look into this.

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<div class="post-metadata">

**Author:** ![gmatege](https://avatars.discourse-cdn.com/v4/letter/g/74df32/32.png) [@gmatege](https://discourse.hibernate.org/u/gmatege)\
**Post date:** [May 29, 2026, 3:29pm UTC](https://discourse.hibernate.org/t/projections-failing-instantiation-exception/12224/5 "2026-05-29T15:29:25Z")

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Try projecting a field of a related entity, One that would need a join - But even for a basic entity, Why would hibernate really require a matching constructor? Most entities only have default constructors - We didn’t change any code for this to come up, Its as a result of upgrading to the latest version and reverting back works very fine…