fix weak bug

hutool-cache/src/test/java/cn/hutool/cache/WeakCacheTest.java

@@ -1,6 +1,7 @@
 package cn.hutool.cache;
 
 import cn.hutool.cache.impl.WeakCache;
+import cn.hutool.core.lang.Console;
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -14,8 +15,31 @@ public class WeakCacheTest {
 
 		Assert.assertEquals(2, cache.size());
 
+		// 检查被MutableObj包装的key能否正常移除
 		cache.remove("abc");
 
 		Assert.assertEquals(1, cache.size());
 	}
+
+	@Test
+	public void removeByGcTest(){
+		WeakCache<String, String> cache = new WeakCache<>(-1);
+		cache.put("a", "1");
+		cache.put("b", "2");
+		Assert.assertEquals(2, cache.size());
+
+		// GC测试
+		int i=0;
+		while(true){
+			if(2 == cache.size()){
+				i++;
+				Console.log("Object is alive for {} loops - ", i);
+				System.gc();
+			}else{
+				Console.log("Object has been collected.");
+				Console.log(cache.size());
+				break;
+			}
+		}
+	}
 }