fix replace Collections.EmptyList with ArrayList for issue #1835

core/src/main/java/com/alibaba/fastjson2/reader/ObjectReaderImplList.java

@@ -236,7 +236,7 @@ public Object createInstance(Collection collection) {
         int size = collection.size();
 
         if (size == 0 && (listClass == List.class)) {
-            Collection list = Collections.emptyList();
+            Collection list = new ArrayList();
             if (builder != null) {
                 return builder.apply(list);
             }

core/src/test/java/com/alibaba/fastjson2/issues_1800/Issue1835.java

@@ -0,0 +1,84 @@
+package com.alibaba.fastjson2.issues_1800;
+
+import com.alibaba.fastjson2.JSON;
+import com.alibaba.fastjson2.JSONObject;
+import org.junit.jupiter.api.Test;
+
+import java.lang.reflect.Method;
+import java.lang.reflect.Type;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class Issue1835 {
+    @Test
+    public void test() {
+        List<Person> sourceList = new ArrayList<>();
+        Set<Person> sourceSet = new HashSet<>();
+        Map<Integer, Person> sourceMap = new HashMap<>();
+        Map<String, Object> source = new HashMap<>();
+        source.put("data", sourceList);
+        source.put("data2", sourceSet);
+        source.put("data3", sourceMap);
+
+        JSONObject target = JSON.parseObject(JSON.toJSONString(source));
+        List<Person> targetList = target.getObject("data", getType("list"));
+        Set<Person> targetSet = target.getObject("data2", getType("set"));
+        Map<Integer, Person> targetMap = target.getObject("data3", getType("map"));
+
+        Person lisi = new Person("lisi");
+        targetList.add(lisi);
+        assertEquals("[{\"name\":\"lisi\"}]", JSON.toJSONString(targetList));
+        targetSet.add(lisi);
+        assertEquals("[{\"name\":\"lisi\"}]", JSON.toJSONString(targetSet));
+        targetMap.put(0, lisi);
+        assertEquals("{0:{\"name\":\"lisi\"}}", JSON.toJSONString(targetMap));
+    }
+
+    public static Type getType(String type) {
+        try {
+            Issue1835 app = new Issue1835();
+            Method method = app.getClass().getMethod(type);
+            return method.getGenericReturnType();
+        } catch (Throwable e) {
+            e.printStackTrace();
+            throw new RuntimeException(e);
+        }
+    }
+
+    public List<Person> list() {
+        return new ArrayList<>();
+    }
+
+    public Set<Person> set() {
+        return new HashSet<>();
+    }
+
+    public Map<Integer, Person> map() {
+        return new HashMap<>();
+    }
+
+    public static class Person {
+        private String name;
+
+        public Person() {
+        }
+
+        public Person(String name) {
+            this.name = name;
+        }
+
+        public String getName() {
+            return name;
+        }
+
+        public void setName(String name) {
+            this.name = name;
+        }
+    }
+}