Introduce conditional activation of Hibernate substitutions

Closes gh-31452

Author: sdeleuze

spring-orm/src/main/java/org/springframework/orm/jpa/vendor/SubstituteOnlyIfPresent.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2002-2023 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.orm.jpa.vendor;
+
+import java.util.function.Predicate;
+
+/**
+ * Predicate intended to enabled the related GraalVM substitution only when the class is present in the classpath.
+ *
+ * @author Sebastien Deleuze
+ * @since 6.1
+ */
+class SubstituteOnlyIfPresent implements Predicate<String> {
+
+	@Override
+	public boolean test(String type) {
+		try {
+			Class.forName(type, false, getClass().getClassLoader());
+			return true;
+		}
+		catch (ClassNotFoundException | NoClassDefFoundError ex) {
+			return false;
+		}
+	}
+}

spring-orm/src/main/java/org/springframework/orm/jpa/vendor/Target_BytecodeProvider.java

@@ -31,7 +31,7 @@
  * @author Sebastien Deleuze
  * @since 6.1
  */
-@TargetClass(className = "org.hibernate.bytecode.internal.none.BytecodeProviderImpl")
+@TargetClass(className = "org.hibernate.bytecode.internal.none.BytecodeProviderImpl", onlyWith = SubstituteOnlyIfPresent.class)
 final class Target_BytecodeProvider {
 
 	@Substitute

spring-orm/src/main/java/org/springframework/orm/jpa/vendor/Target_BytecodeProviderInitiator.java

@@ -32,7 +32,7 @@
  * @author Sebastien Deleuze
  * @since 6.1
  */
-@TargetClass(className = "org.hibernate.bytecode.internal.BytecodeProviderInitiator")
+@TargetClass(className = "org.hibernate.bytecode.internal.BytecodeProviderInitiator", onlyWith = SubstituteOnlyIfPresent.class)
 final class Target_BytecodeProviderInitiator {
 
 	@Alias