Switch to JPA 3.2 `Query.getSingleResultOrNull()`

[david-kubecka]

I'm talking about this code: https://github.com/spring-projects/spring-data-jpa/blob/main/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/JpaQueryExecution.java#L224. As we know, getSingleResult throws an exception upon a non-existing entity. Since this is an allowed situation the exception is caught here https://github.com/spring-projects/spring-data-jpa/blob/main/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/JpaQueryExecution.java#L92.

I wonder why this try/catch approach (generally frowned upon) is used here instead of an alternative approach using getResultList, see e.g. https://stackoverflow.com/a/2885024/13015027. Apart from a slight performance penalty (not measured), the biggest problem of the current approach is that the exception is captured by telemetry agents (see open-telemetry/opentelemetry-java-instrumentation#12125).

[mp911de]

the biggest problem of the current approach is that it pollutes the logs.

Care to elaborate? There should be no logging involved from our side. We could actually switch to uniqueResultOptional. Just noticed that uniqueResultOptional is Hibernate-specific and not something that JPA defines.

Looking at the getSingleResult implementations, implementations use it merely as wrapper for getResultList post-processing.

[david-kubecka]

I've clarified the issue with a link (which I've found meanwhile) to an opentelemtry issue.

[mp911de]

This ticket is a duplicate of #3633

[david-kubecka]

Ok, the linked ticket has a much better description of the underlying OTEL problem.

Still, I would like to understand why it wouldn't be possible to replace the current getSingleResult call with an approach similar to the linked SO answer. AFAIK that one doesn't rely on anything Hbernate specific, utilizing plain JPA only.

[mp911de]

We comply with the JPA spec by using getSingleResult(). If we now change (after using that functionality for almost 15 years) to a different strategy, I am pretty sure that we will break someone else's application because, in some particular cases, Hibernate (or Eclipselink) is doing things in getSingleResult() slightly differently than in getResultList().