SpringPersistenceUnitInfo leniently ignores transformer if no LoadTimeWeaver is present

Closes gh-29736

Author: jhoeller

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * 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.
@@ -17,6 +17,7 @@
 package org.springframework.orm.jpa.persistenceunit;
 
 import jakarta.persistence.spi.ClassTransformer;
+import org.apache.commons.logging.LogFactory;
 
 import org.springframework.core.DecoratingClassLoader;
 import org.springframework.instrument.classloading.LoadTimeWeaver;
@@ -79,10 +80,12 @@ public ClassLoader getClassLoader() {
 	 */
 	@Override
 	public void addTransformer(ClassTransformer classTransformer) {
-		if (this.loadTimeWeaver == null) {
-			throw new IllegalStateException("Cannot apply class transformer without LoadTimeWeaver specified");
+		if (this.loadTimeWeaver != null) {
+			this.loadTimeWeaver.addTransformer(new ClassFileTransformerAdapter(classTransformer));
+		}
+		else {
+			LogFactory.getLog(getClass()).info("No LoadTimeWeaver setup: ignoring JPA class transformer");
 		}
-		this.loadTimeWeaver.addTransformer(new ClassFileTransformerAdapter(classTransformer));
 	}
 
 	/**