fix parse private class error, for issue #3134

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

@@ -3032,7 +3032,9 @@ private <T> int genReadFieldValue(
 
             if (list) {
                 Class itemClass = TypeUtils.getMapping(itemType);
-                if (itemClass != null && Collection.class.isAssignableFrom(itemClass)) {
+                if (itemClass != null
+                        && (Collection.class.isAssignableFrom(itemClass) || !Modifier.isPublic(itemClass.getModifiers()))
+                ) {
                     list = false;
                 }
             }

core/src/test/java/com/alibaba/fastjson2/issues_3100/Issue3134.java

@@ -0,0 +1,37 @@
+package com.alibaba.fastjson2.issues_3100;
+
+import com.alibaba.fastjson2.JSON;
+import com.alibaba.fastjson2.JSONArray;
+import com.alibaba.fastjson2.JSONObject;
+import lombok.Data;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class Issue3134 {
+    @Test
+    public void test() {
+        String json = "{\"name\":\"希望小学\",\"students\":{\"age\":\"12\",\"id\":\"1\",\"name\":\"张宇\"}}";
+        School schoolOne = JSON.parseObject(json, School.class);
+        JSONObject schoolTwo = JSON.parseObject(json);
+        School schoolThree = schoolTwo.toJavaObject(School.class);
+        JSONObject studentOne = schoolTwo.getJSONObject("students");
+        JSONArray studentTwo = schoolTwo.getJSONArray("students");
+        assertEquals("[{\"age\":\"12\",\"id\":\"1\",\"name\":\"张宇\"}]", studentTwo.toString());
+    }
+
+    @Data
+    private static class School{
+        private String name;
+        private List<Student> students;
+    }
+
+    @Data
+    private static class Student{
+        private String name;
+        private String id;
+        private String age;
+    }
+}