Adapt to getAllClassNames SPI (post JPA 4.0 M1)

See gh-35705

spring-orm/src/main/java/org/springframework/orm/jpa/persistenceunit/PersistenceManagedTypesScanner.java

@@ -18,6 +18,7 @@ package org.springframework.orm.jpa.persistenceunit;
 
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.lang.annotation.Annotation;
 import java.net.URL;
 import java.util.ArrayList;
 import java.util.HashSet;
@@ -72,6 +73,15 @@ public final class PersistenceManagedTypesScanner {
 		entityTypeFilters.add(new AnnotationTypeFilter(Embeddable.class, false));
 		entityTypeFilters.add(new AnnotationTypeFilter(MappedSuperclass.class, false));
 		entityTypeFilters.add(new AnnotationTypeFilter(Converter.class, false));
+		try {
+			@SuppressWarnings("unchecked")
+			Class<? extends Annotation> discoverable = (Class<? extends Annotation>) ClassUtils.forName(
+					"jakarta.persistence.spi.Discoverable", PersistenceManagedTypesScanner.class.getClassLoader());
+			entityTypeFilters.add(new AnnotationTypeFilter(discoverable, true));
+		}
+		catch (ClassNotFoundException ex) {
+			// JPA 4.0 API not present - simply skip.
+		}
 	}
 
 	private final ResourcePatternResolver resourcePatternResolver;
@@ -147,7 +157,7 @@ public final class PersistenceManagedTypesScanner {
 							}
 						}
 					}
-					else if (className.endsWith(PACKAGE_INFO_SUFFIX)) {
+					if (className.endsWith(PACKAGE_INFO_SUFFIX)) {
 						scanResult.managedPackages.add(className.substring(0,
 								className.length() - PACKAGE_INFO_SUFFIX.length()));
 					}

spring-orm/src/main/java/org/springframework/orm/jpa/persistenceunit/SpringPersistenceUnitInfo.java

@@ -262,16 +262,13 @@ public class SpringPersistenceUnitInfo extends MutablePersistenceUnitInfo {
 				// Fast path for SmartPersistenceUnitInfo JTA check
 				return (getTransactionType() == PersistenceUnitTransactionType.JTA);
 			}
-			else if (method.getName().equals("getAllManagedClassNames")) {
-				// JPA 4.0 letting the container perform the scanning ->
-				// with Spring, only makes sense with typical default persistence unit.
-				if (excludeUnlistedClasses() && getMappingFileNames().isEmpty()) {
-					List<String> mergedClassesAndPackages = new ArrayList<>(getManagedClassNames());
-					mergedClassesAndPackages.addAll(getManagedPackages());
-					return mergedClassesAndPackages;
+			else if (method.getName().equals("getAllClassNames")) {
+				// JPA 4.0 letting the container perform the scanning
+				if (excludeUnlistedClasses()) {
+					return getManagedClassNames();  // typically coming from Spring default persistence unit
 				}
 				throw new UnsupportedOperationException(
-						"JPA 4.0 getAllManagedClassNames only supported with exclude-unlisted-classes and no orm.xml");
+						"JPA 4.0 getAllClassNames only supported with exclude-unlisted-classes");
 			}
 
 			// Regular methods to be delegated to SpringPersistenceUnitInfo