修复ConcurrentHashMap.computeIfAbsent缺陷导致的问题

CHANGELOG.md

@@ -18,6 +18,7 @@
 * 【db     】     修复Hive2驱动无法识别问题（issue#2606@Github）
 * 【core   】     修复computeIfAbsent问题（issue#I5PTN3@Gitee）
 * 【extra  】     修复Ftp中路径问题（issue#I5R2DE@Gitee）
+* 【core   】     修复ConcurrentHashMap.computeIfAbsent缺陷导致的问题
 
 -------------------------------------------------------------------------------------------------------------
 

hutool-core/src/main/java/cn/hutool/core/bean/BeanDescCache.java

@@ -1,6 +1,7 @@
 package cn.hutool.core.bean;
 
 import cn.hutool.core.lang.func.Func0;
+import cn.hutool.core.map.MapUtil;
 import cn.hutool.core.map.WeakConcurrentMap;
 
 /**
@@ -23,7 +24,7 @@ public enum BeanDescCache {
 	 * @since 5.4.2
 	 */
 	public BeanDesc getBeanDesc(Class<?> beanClass, Func0<BeanDesc> supplier) {
-		return bdCache.computeIfAbsent(beanClass, (key)->supplier.callWithRuntimeException());
+		return MapUtil.computeIfAbsent(bdCache, beanClass, (key)->supplier.callWithRuntimeException());
 	}
 
 	/**

hutool-core/src/main/java/cn/hutool/core/lang/Singleton.java

@@ -1,6 +1,7 @@
 package cn.hutool.core.lang;
 
 import cn.hutool.core.lang.func.Func0;
+import cn.hutool.core.map.MapUtil;
 import cn.hutool.core.util.ArrayUtil;
 import cn.hutool.core.util.ClassUtil;
 import cn.hutool.core.util.ReflectUtil;
@@ -52,15 +53,7 @@ public final class Singleton {
 	 */
 	@SuppressWarnings("unchecked")
 	public static <T> T get(String key, Func0<T> supplier) {
-		//return (T) POOL.computeIfAbsent(key, (k)-> supplier.callWithRuntimeException());
+		return (T) MapUtil.computeIfAbsent(POOL, key, (k)-> supplier.callWithRuntimeException());
-		// issues#2349
-		// ConcurrentHashMap.computeIfAbsent在某些情况下会导致死循环问题，此处采用Dubbo的解决方案
-		Object value = POOL.get(key);
-		if(null == value){
-			POOL.putIfAbsent(key, supplier.callWithRuntimeException());
-			value = POOL.get(key);
-		}
-		return (T) value;
 	}
 
 	/**

hutool-core/src/main/java/cn/hutool/core/map/MapUtil.java

@@ -1464,17 +1464,19 @@ public class MapUtil {
 	}
 
 	/**
-	 * 方法来自MyBatis，解决使用ConcurrentHashMap.computeIfAbsent导致的死循环问题。<br>
+	 * 方法来自Dubbo，解决使用ConcurrentHashMap.computeIfAbsent导致的死循环问题。<br>
+	 * issues#2349<br>
 	 * A temporary workaround for Java 8 specific performance issue JDK-8161372 .<br>
 	 * This class should be removed once we drop Java 8 support.
 	 *
 	 * @see <a href="https://bugs.openjdk.java.net/browse/JDK-8161372">https://bugs.openjdk.java.net/browse/JDK-8161372</a>
 	 */
 	public static <K, V> V computeIfAbsent(Map<K, V> map, K key, Function<K, V> mappingFunction) {
-		final V value = map.get(key);
+		V value = map.get(key);
-		if (value != null) {
+		if(null == value){
+			map.putIfAbsent(key, mappingFunction.apply(key));
+			value = map.get(key);
+		}
 		return value;
 	}
-		return map.computeIfAbsent(key, mappingFunction);
-	}
 }

hutool-core/src/main/java/cn/hutool/core/util/ClassLoaderUtil.java

@@ -5,6 +5,7 @@ import cn.hutool.core.exceptions.UtilException;
 import cn.hutool.core.lang.Assert;
 import cn.hutool.core.lang.JarClassLoader;
 import cn.hutool.core.lang.Pair;
+import cn.hutool.core.map.MapUtil;
 import cn.hutool.core.map.WeakConcurrentMap;
 import cn.hutool.core.text.CharPool;
 
@@ -50,7 +51,7 @@ public class ClassLoaderUtil {
 	 * 原始类型名和其class对应表，例如：int =》 int.class
 	 */
 	private static final Map<String, Class<?>> PRIMITIVE_TYPE_NAME_MAP = new ConcurrentHashMap<>(32);
-	private static final WeakConcurrentMap<Pair<String, ClassLoader>, Class<?>> CLASS_CACHE = new WeakConcurrentMap<>();
+	private static final Map<Pair<String, ClassLoader>, Class<?>> CLASS_CACHE = new WeakConcurrentMap<>();
 
 	static {
 		List<Class<?>> primitiveTypes = new ArrayList<>(32);
@@ -199,7 +200,7 @@ public class ClassLoaderUtil {
 		if (clazz == null) {
 			final String finalName = name;
 			final ClassLoader finalClassLoader = classLoader;
-			clazz = CLASS_CACHE.computeIfAbsent(Pair.of(name, classLoader), (key)-> doLoadClass(finalName, finalClassLoader, isInitialized));
+			clazz = MapUtil.computeIfAbsent(CLASS_CACHE, Pair.of(name, classLoader), (key)-> doLoadClass(finalName, finalClassLoader, isInitialized));
 		}
 		return clazz;
 	}