SingletonEhCacheRegionFactory is no longer available when upgrading from Hibernate 5.2 to 5.3

Question

A project I work on is currently using Hibernate version 5.2.15.Final. When configuring the second-level cache, the project has been using org.hibernate.cache.ehcache.SingletonEhCacheRegionFactory as the value for hibernate.cache.region.factory_class .

When I change the Hibernate version to 5.3.12.Final, SingletonEhCacheRegionFactory is no longer in that package. A class with that same name is available in the net.sf.ehcache.hibernate package, and I can use that with no compilation errors. But if I run it I get an error when it tries to build a session:

org.hibernate.service.spi.ServiceException: Unable to create requested service [org.hibernate.cache.spi.RegionFactory]

    at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:275)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:237)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214)
    at org.hibernate.boot.internal.MetadataBuilderImpl$MetadataBuildingOptionsImpl.<init>(MetadataBuilderImpl.java:688)
    at org.hibernate.boot.internal.MetadataBuilderImpl.<init>(MetadataBuilderImpl.java:123)
    at org.hibernate.boot.internal.MetadataBuilderImpl.<init>(MetadataBuilderImpl.java:93)

If I dig deeper into the stack trace, the real error seems to be this:

Caused by: org.hibernate.boot.registry.selector.spi.StrategySelectionException: Unable to resolve name [net.sf.ehcache.hibernate.SingletonEhCacheRegionFactory] as strategy [org.hibernate.cache.spi.RegionFactory]
    at org.hibernate.boot.registry.selector.internal.StrategySelectorImpl.selectStrategyImplementor(StrategySelectorImpl.java:133)
    at org.hibernate.boot.registry.selector.internal.StrategySelectorImpl.resolveStrategy(StrategySelectorImpl.java:212)
    at org.hibernate.boot.registry.selector.internal.StrategySelectorImpl.resolveStrategy(StrategySelectorImpl.java:169)
    at org.hibernate.cache.internal.RegionFactoryInitiator.resolveRegionFactory(RegionFactoryInitiator.java:93)
    at org.hibernate.cache.internal.RegionFactoryInitiator.initiateService(RegionFactoryInitiator.java:47)
    at org.hibernate.cache.internal.RegionFactoryInitiator.initiateService(RegionFactoryInitiator.java:32)
    at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:94)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:263)
    ... 64 more
Caused by: org.hibernate.boot.registry.classloading.spi.ClassLoadingException: Unable to load class [net.sf.ehcache.hibernate.SingletonEhCacheRegionFactory]
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:137)
    at org.hibernate.boot.registry.selector.internal.StrategySelectorImpl.selectStrategyImplementor(StrategySelectorImpl.java:129)
    ... 71 more
Caused by: java.lang.NoClassDefFoundError: org/hibernate/cache/QueryResultsRegion
    at java.base/java.lang.Class.forName0(Native Method)
    at java.base/java.lang.Class.forName(Class.java:374)
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:131)
    ... 72 more
Caused by: java.lang.ClassNotFoundException: org.hibernate.cache.QueryResultsRegion
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:582)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:190)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:499)
    ... 75 more

Here's what my pom.xml dependencies look like:

<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-core</artifactId>
    <version>5.3.12.Final</version>
</dependency>
<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-ehcache</artifactId>
    <version>5.3.12.Final</version>
</dependency>

<dependency>
    <groupId>net.sf.ehcache</groupId>
    <artifactId>ehcache-core</artifactId>
    <version>2.6.11</version>
    <exclusions>
        <exclusion>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-c3p0</artifactId>
    <version>5.3.12.Final</version>
</dependency>

Answer 1

Okay, I think I figured out the problem. Previously my code had been fetching the full class name and path by doing:

SingletonEhCacheRegionFactory.class.getCanonicalName()

But in Hibernate 5.3 the class had been moved to an internal package, which is why I could no longer find it. If I used a hardcoded string with the old package name ( "org.hibernate.cache.ehcache.SingletonEhCacheRegionFactory" ), I no longer get that exception.