add test

hutool-core/src/test/java/cn/hutool/core/map/Issue2349Test.java

@@ -0,0 +1,22 @@
+package cn.hutool.core.map;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.concurrent.ConcurrentHashMap;
+
+public class Issue2349Test {
+
+	@Test
+	public void computeIfAbsentTest(){
+		// https://blog.csdn.net/xiaochao_bos/article/details/103789991
+		// 使用ConcurrentHashMap会造成死循环
+		// SafeConcurrentHashMap用于修复此问题
+		final ConcurrentHashMap<String,Integer> map=new SafeConcurrentHashMap<>(16);
+		map.computeIfAbsent("AaAa", key->map.computeIfAbsent("BBBB",key2->42));
+
+		Assert.assertEquals(2, map.size());
+		Assert.assertEquals(Integer.valueOf(42), map.get("AaAa"));
+		Assert.assertEquals(Integer.valueOf(42), map.get("BBBB"));
+	}
+}