fix bug for issue #3419

core/src/main/java/com/alibaba/fastjson2/JSONArray.java

@@ -203,6 +203,14 @@ public JSONObject getJSONObject(int index) {
             return object;
         }
 
+        if (value instanceof Map.Entry) {
+            Map.Entry entry = (Map.Entry) value;
+            JSONObject object = new JSONObject();
+            object.put(entry.getKey().toString(), entry.getValue());
+            set(index, object);
+            return object;
+        }
+
         Class valueClass = value.getClass();
         ObjectWriter objectWriter = JSONFactory.getDefaultObjectWriterProvider().getObjectWriter(valueClass);
         if (objectWriter instanceof ObjectWriterAdapter) {

core/src/main/java/com/alibaba/fastjson2/writer/ObjectWriterAdapter.java

@@ -675,6 +675,13 @@ public JSONObject toJSONObject(T object, long features) {
             if (fieldValue == object) {
                 fieldValue = jsonObject;
             }
+
+            if (fieldValue instanceof Enum) {
+                if ((features & WriteEnumsUsingName.mask) != 0) {
+                    fieldValue = ((Enum) fieldValue).name();
+                }
+            }
+
             if (fieldWriter instanceof FieldWriterObject && !(fieldValue instanceof Map)) {
                 ObjectWriter valueWriter = fieldWriter.getInitWriter();
                 if (valueWriter == null) {

core/src/test/java/com/alibaba/fastjson2/issues_3400/Issue3419

@@ -0,0 +1,29 @@
+package com.alibaba.fastjson2.issues_3400;
+
+import com.alibaba.fastjson2.JSONArray;
+import com.alibaba.fastjson2.JSONObject;
+import org.junit.jupiter.api.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class Issue3419 {
+    @Test
+    public void test() {
+        Map<String, Object> map = new HashMap<>();
+        map.put("str", new float[] {1.0f, 1.0f, 1.0f, 1.0f, 1.0f});
+        map.put("str2", new float[] {2.0f, 2.0f, 2.0f, 2.0f, 2.0f});
+
+        JSONObject jo = new JSONObject();
+        JSONArray ja = new JSONArray();
+        ja.addAll(map.entrySet());
+        jo.put("content", ja);
+
+        JSONObject obj = jo.getJSONArray("content").getJSONObject(0);
+        assertEquals(obj.toString(), "{\"str\":[1.0,1.0,1.0,1.0,1.0]}");
+        JSONObject obj2 = jo.getJSONArray("content").getJSONObject(1);
+        assertEquals(obj2.toString(), "{\"str2\":[2.0,2.0,2.0,2.0,2.0]}");
+    }
+}

core/src/test/java/com/alibaba/fastjson2/issues_3400/Issue3464.java

@@ -0,0 +1,27 @@
+package com.alibaba.fastjson2.issues_3400;
+
+import com.alibaba.fastjson2.JSON;
+import com.alibaba.fastjson2.JSONObject;
+import com.alibaba.fastjson2.JSONWriter;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import org.junit.Test;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.concurrent.TimeUnit;
+
+public class Issue3464 {
+
+    @Test
+    public void test() {
+        Data data = new Data(TimeUnit.MINUTES);
+        JSONObject json = (JSONObject) JSON.toJSON(data, JSONWriter.Feature.WriteEnumsUsingName);
+        assertEquals(json.get("unit").getClass().toString(), "class java.lang.String");
+    }
+
+    @Getter
+    @AllArgsConstructor
+    private static class Data {
+        private TimeUnit unit;
+    }
+}