[add] map vs hashMap

CodeCoderCoding · CodeCoderCoding · commit 2a6c2d1c2d90 · 2022-09-20T13:37:01.000+08:00
diff --git a/src/DGenericContainer/Map_HashMap/MapHashMap.java b/src/DGenericContainer/Map_HashMap/MapHashMap.java
@@ -0,0 +1,30 @@
+package DGenericContainer.Map_HashMap;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * @ClassName MapHashMap
+ * @Description
+ * @Date 2022/9/20 11:39
+ * @Version 1.0.0
+ **/
+public class MapHashMap {
+    public static void main(String[] args) {
+        HashMap<String, String> hashMap=new HashMap<>();
+        //错误示例：Collections.emptyMap()的返回类型为Map
+        //HashMap<String, String> hashMap1=Collections.emptyMap();
+        useHashMap(hashMap);
+        Map<String, String> map=new HashMap<>();
+        //错误示例：方法参数为hashMap类型
+        //useHashMap(map);
+        Map<String, String> map1= Collections.emptyMap();
+        //错误示例：方法参数为hashMap类型
+        //useHashMap(map1);
+    }
+
+    public static void useHashMap(HashMap<String, String> hashMap){
+
+    }
+}
