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I am implementing a program in Spring-Boot using ObjectDB. To actually use ObjectDB I have followed this approach https://www.objectdb.com/forum/2523 which is working perfectly.

However, as soon as I want to use Spring-Actuator then I am getting the following errors:

Error creating bean with name 'org.springframework.boot.actuate.autoconfigure.metrics.orm.jpa.HibernateMetricsAutoConfiguration': Injection of autowired dependencies failed; nested exception is com.objectdb.o.UserException: Unsupported unwrap(org.hibernate.SessionFactory.class) for EntityManagerFactory

Any ideas on how to solve this error?

I am using the exact same code as in the link. I have added Spring-Actuator in the pom like this:

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
DwnBrd
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1 Answers1

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The failure is occurring because Spring Boot is trying to unwrap the JPA EntityManagerFactory to get Hibernate's SessionFactory. It's attempting to do this as you have Hibernate on the classpath (it's a dependency of spring-boot-starter-data-jpa). According to the JPA specification, unwrap should throw a PersistenceException "if the provider does not support the call". Spring Boot catches PersistenceException in case unwrap isn't supported. Unfortunately, ObjectDB is throwing com.objectdb.o.UserException which isn't spec compliant. I'd recommend raising this as an ObjectDB bug.

You can avoid the problem by excluding Hibernate from the classpath. This will stop Spring Boot from attempting to unwrap Hibernate's SessionFactory, preventing the ObjectDB bug from occurring. You can do so by adding an exclusion to the spring-boot-starter-data-jpa dependency in your pom.xml:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
    <exclusions>
        <exclusion>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
        </exclusion>
    </exclusions>
</dependency>
Andy Wilkinson
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  • Thanks for the report and the diagnosis. ObjectDB 2.8.4 was fixed to throw an instance of PersistenceException on unsupported unwrap calls (actually an instance of a subclass, but hopefully it would be caught now as expected). – ObjectDB Feb 06 '21 at 23:14
  • Yes, thanks! I can confirm that both solutions (adding the exclusion and/or upgrading ObjectDB) work. – DwnBrd Feb 07 '21 at 09:02