Try late locking for waiting on specific bean to be finished

Closes spring-projectsgh-34186

Author: jhoeller

spring-beans/src/main/java/org/springframework/beans/factory/support/DefaultSingletonBeanRegistry.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -279,7 +279,25 @@ public Object getSingleton(String beanName, ObjectFactory<?> singletonFactory) {
 				if (logger.isDebugEnabled()) {
 					logger.debug("Creating shared instance of singleton bean '" + beanName + "'");
 				}
-				beforeSingletonCreation(beanName);
+
+				try {
+					beforeSingletonCreation(beanName);
+				}
+				catch (BeanCurrentlyInCreationException ex) {
+					if (locked) {
+						throw ex;
+					}
+					// Try late locking for waiting on specific bean to be finished.
+					this.singletonLock.lock();
+					locked = true;
+					// Singleton object should have appeared in the meantime.
+					singletonObject = this.singletonObjects.get(beanName);
+					if (singletonObject != null) {
+						return singletonObject;
+					}
+					beforeSingletonCreation(beanName);
+				}
+
 				boolean newSingleton = false;
 				boolean recordSuppressedExceptions = (locked && this.suppressedExceptions == null);
 				if (recordSuppressedExceptions) {

spring-beans/src/test/java/org/springframework/beans/factory/BeanFactoryLockingTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -23,7 +23,6 @@
 import org.springframework.beans.testfixture.beans.TestBean;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 
 /**
  * @author Juergen Hoeller
@@ -56,9 +55,6 @@ public void setBeanFactory(BeanFactory beanFactory) {
 		@Override
 		public void afterPropertiesSet() throws Exception {
 			Thread thread = new Thread(() -> {
-				// Fail for circular reference from other thread
-				assertThatExceptionOfType(BeanCurrentlyInCreationException.class).isThrownBy(() ->
-						beanFactory.getBean(ThreadDuringInitialization.class));
 				// Leniently create unrelated other bean outside of singleton lock
 				assertThat(beanFactory.getBean(TestBean.class).getName()).isEqualTo("tb");
 				// Creation attempt in other thread was successful