Stop configuring metrics if hibernate is not available

Closes gh-15317

Author: snicoll

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/orm/jpa/HibernateMetricsAutoConfiguration.java

@@ -23,6 +23,7 @@
 
 import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.binder.jpa.HibernateMetrics;
+import org.hibernate.SessionFactory;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.actuate.autoconfigure.metrics.MetricsAutoConfiguration;
@@ -46,7 +47,8 @@
 @Configuration
 @AutoConfigureAfter({ MetricsAutoConfiguration.class, HibernateJpaAutoConfiguration.class,
 		SimpleMetricsExportAutoConfiguration.class })
-@ConditionalOnClass({ EntityManagerFactory.class, MeterRegistry.class })
+@ConditionalOnClass({ EntityManagerFactory.class, SessionFactory.class,
+		MeterRegistry.class })
 @ConditionalOnBean({ EntityManagerFactory.class, MeterRegistry.class })
 public class HibernateMetricsAutoConfiguration {
 

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/metrics/orm/jpa/HibernateMetricsAutoConfigurationTests.java

@@ -37,6 +37,7 @@
 import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
 import org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration;
 import org.springframework.boot.orm.jpa.EntityManagerFactoryBuilder;
+import org.springframework.boot.test.context.FilteredClassLoader;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -53,6 +54,7 @@
  * Tests for {@link HibernateMetricsAutoConfiguration}.
  *
  * @author Rui Figueira
+ * @author Stephane Nicoll
  */
 public class HibernateMetricsAutoConfigurationTests {
 
@@ -137,6 +139,19 @@ public void entityManagerFactoryInstrumentationIsDisabledIfNotHibernateSessionFa
 				});
 	}
 
+	@Test
+	public void entityManagerFactoryInstrumentationIsDisabledIfHibernateIsNotAvailable() {
+		this.contextRunner.withClassLoader(new FilteredClassLoader(SessionFactory.class))
+				.withUserConfiguration(
+						NonHibernateEntityManagerFactoryConfiguration.class)
+				.run((context) -> {
+					assertThat(context)
+							.doesNotHaveBean(HibernateMetricsAutoConfiguration.class);
+					MeterRegistry registry = context.getBean(MeterRegistry.class);
+					assertThat(registry.find("hibernate.statements").meter()).isNull();
+				});
+	}
+
 	@Configuration
 	static class BaseConfiguration {