Align ConcurrentMapCacheManager locking behavior with CaffeineCacheManager

Closes gh-30780

(cherry picked from commit 60865ea)

Author: jhoeller

spring-context-support/src/main/java/org/springframework/cache/caffeine/CaffeineCacheManager.java

@@ -189,13 +189,11 @@ public Collection<String> getCacheNames() {
 	@Override
 	@Nullable
 	public Cache getCache(String name) {
-		if (this.dynamic) {
-			Cache cache = this.cacheMap.get(name);
-			return (cache != null) ? cache : this.cacheMap.computeIfAbsent(name, this::createCaffeineCache);
-		}
-		else {
-			return this.cacheMap.get(name);
+		Cache cache = this.cacheMap.get(name);
+		if (cache == null && this.dynamic) {
+			cache = this.cacheMap.computeIfAbsent(name, this::createCaffeineCache);
 		}
+		return cache;
 	}
 
 

spring-context/src/main/java/org/springframework/cache/concurrent/ConcurrentMapCacheManager.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 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.
@@ -166,13 +166,7 @@ public Collection<String> getCacheNames() {
 	public Cache getCache(String name) {
 		Cache cache = this.cacheMap.get(name);
 		if (cache == null && this.dynamic) {
-			synchronized (this.cacheMap) {
-				cache = this.cacheMap.get(name);
-				if (cache == null) {
-					cache = createConcurrentMapCache(name);
-					this.cacheMap.put(name, cache);
-				}
-			}
+			cache = this.cacheMap.computeIfAbsent(name, this::createConcurrentMapCache);
 		}
 		return cache;
 	}