Polish "Disable Hibernate entity scanning for default JPA setup"

Closes gh-15565

Author: snicoll

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/orm/jpa/HibernateProperties.java

@@ -27,20 +27,22 @@
 import org.springframework.boot.orm.jpa.hibernate.SpringImplicitNamingStrategy;
 import org.springframework.boot.orm.jpa.hibernate.SpringPhysicalNamingStrategy;
 import org.springframework.util.Assert;
+import org.springframework.util.ClassUtils;
 import org.springframework.util.ObjectUtils;
 import org.springframework.util.StringUtils;
 
 /**
  * Configuration properties for Hibernate.
  *
  * @author Stephane Nicoll
- * @author Artsiom Yudovin
  * @since 2.1.0
  * @see JpaProperties
  */
 @ConfigurationProperties("spring.jpa.hibernate")
 public class HibernateProperties {
 
+	private static final String DISABLED_SCANNER_CLASS = "org.hibernate.boot.archive.scan.internal.DisabledScanner";
+
 	private final Naming naming = new Naming();
 
 	/**
@@ -96,7 +98,7 @@ private Map<String, Object> getAdditionalProperties(Map<String, String> existing
 			HibernateSettings settings) {
 		Map<String, Object> result = new HashMap<>(existing);
 		applyNewIdGeneratorMappings(result);
-		applyArchiveScanner(result);
+		applyScanner(result);
 		getNaming().applyNamingStrategies(result);
 		String ddlAuto = determineDdlAuto(existing, settings::getDdlAuto);
 		if (StringUtils.hasText(ddlAuto) && !"none".equals(ddlAuto)) {
@@ -123,10 +125,10 @@ else if (!result.containsKey(AvailableSettings.USE_NEW_ID_GENERATOR_MAPPINGS)) {
 		}
 	}
 
-	private void applyArchiveScanner(Map<String, Object> result) {
-		if (!result.containsKey(AvailableSettings.SCANNER)) {
-			result.put(AvailableSettings.SCANNER,
-					"org.hibernate.boot.archive.scan.internal.DisabledScanner");
+	private void applyScanner(Map<String, Object> result) {
+		if (!result.containsKey(AvailableSettings.SCANNER)
+				&& ClassUtils.isPresent(DISABLED_SCANNER_CLASS, null)) {
+			result.put(AvailableSettings.SCANNER, DISABLED_SCANNER_CLASS);
 		}
 	}
 

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/orm/jpa/HibernatePropertiesTests.java

@@ -125,22 +125,22 @@ public void useNewIdGeneratorMappingsFalse() {
 	}
 
 	@Test
-	public void useArchiveScanner() {
+	public void scannerUsesDisabledScannerByDefault() {
+		this.contextRunner.run(assertHibernateProperties(
+				(hibernateProperties) -> assertThat(hibernateProperties).containsEntry(
+						AvailableSettings.SCANNER,
+						"org.hibernate.boot.archive.scan.internal.DisabledScanner")));
+	}
+
+	@Test
+	public void scannerCanBeCustomized() {
 		this.contextRunner.withPropertyValues(
 				"spring.jpa.properties.hibernate.archive.scanner:org.hibernate.boot.archive.scan.internal.StandardScanner")
 				.run(assertHibernateProperties((hibernateProperties) -> assertThat(
 						hibernateProperties).containsEntry(AvailableSettings.SCANNER,
 								"org.hibernate.boot.archive.scan.internal.StandardScanner")));
 	}
 
-	@Test
-	public void defaultArchiveScanner() {
-		this.contextRunner.run(assertHibernateProperties(
-				(hibernateProperties) -> assertThat(hibernateProperties).containsEntry(
-						AvailableSettings.SCANNER,
-						"org.hibernate.boot.archive.scan.internal.DisabledScanner")));
-	}
-
 	@Test
 	public void defaultDdlAutoIsNotInvokedIfPropertyIsSet() {
 		this.contextRunner.withPropertyValues("spring.jpa.hibernate.ddl-auto=validate")