HHH-15415 Jakarta JsonB integration to not break GraalVM native image compilation

hibernate-core/src/main/java/org/hibernate/boot/internal/SessionFactoryOptionsBuilder.java

@@ -71,10 +71,9 @@ import org.hibernate.resource.transaction.spi.TransactionCoordinatorBuilder;
 import org.hibernate.service.spi.ServiceRegistryImplementor;
 import org.hibernate.stat.Statistics;
 import org.hibernate.type.FormatMapper;
-import org.hibernate.type.JacksonJsonFormatMapper;
 import org.hibernate.type.JaxbXmlFormatMapper;
-import org.hibernate.type.JsonBJsonFormatMapper;
 import org.hibernate.type.jackson.JacksonIntegration;
+import org.hibernate.type.jakartajson.JakartaJsonIntegration;
 
 import static org.hibernate.cfg.AvailableSettings.ALLOW_JTA_TRANSACTION_ACCESS;
 import static org.hibernate.cfg.AvailableSettings.ALLOW_REFRESH_DETACHED_ENTITY;
@@ -801,15 +800,9 @@ public class SessionFactoryOptionsBuilder implements SessionFactoryOptions {
 					if (jsonJacksonFormatMapper != null) {
 						return jsonJacksonFormatMapper;
 					}
-					try {
+					else {
-						// Force initialization of the instance
+						return JakartaJsonIntegration.getJakartaJsonBFormatMapperOrNull();
-						JsonBJsonFormatMapper.INSTANCE.hashCode();
-						return JsonBJsonFormatMapper.INSTANCE;
 					}
-					catch (NoClassDefFoundError ex) {
-						// Ignore
-					}
-					return null;
 				}
 		);
 	}

hibernate-core/src/main/java/org/hibernate/type/jakartajson/JakartaJsonIntegration.java

@@ -0,0 +1,37 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.type.jakartajson;
+
+import org.hibernate.type.FormatMapper;
+import org.hibernate.type.JsonBJsonFormatMapper;
+
+public final class JakartaJsonIntegration {
+
+	// Implementation note: we rely on the following two fields to be folded as constants
+	// when GraalVM native image is initializing them.
+	private static final boolean JAKARTA_JSON_AVAILABLE = ableToLoadJakartaJsonB();
+	private static final JsonBJsonFormatMapper JSON_FORMAT_MAPPER = JAKARTA_JSON_AVAILABLE ? new JsonBJsonFormatMapper() : null;
+
+	private JakartaJsonIntegration() {
+		//To not be instantiated: static helpers only
+	}
+
+	private static boolean ableToLoadJakartaJsonB() {
+		try {
+			JakartaJsonIntegration.class.getClassLoader().loadClass( "jakarta.json.bind.Jsonb" );
+			return true;
+		}
+		catch (ClassNotFoundException | LinkageError e) {
+			return false;
+		}
+	}
+
+	public static FormatMapper getJakartaJsonBFormatMapperOrNull() {
+		return JSON_FORMAT_MAPPER;
+	}
+
+}