Fix: Fix Issue1819

core/pom.xml

@@ -225,6 +225,12 @@
             <artifactId>commons-lang3</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.apache.dubbo</groupId>
+            <artifactId>dubbo</artifactId>
+            <version>3.2.5</version>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>org.gitlab4j</groupId>
             <artifactId>gitlab4j-api</artifactId>

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

@@ -1076,7 +1076,7 @@ public List readArray() {
                 offset += 3;
                 value = int3;
             } else if (valueType == BC_INT32) {
-                int int32Value = UNSAFE.getInt(bytes, ARRAY_BYTE_BASE_OFFSET + offset);
+                int int32Value = UNSAFE.getInt(bytes, ARRAY_BYTE_BASE_OFFSET + offset + 1);
                 offset += 5;
                 value = BIG_ENDIAN ? int32Value : Integer.reverseBytes(int32Value);
             } else if (valueType == BC_REFERENCE) {

core/src/test/java/com/alibaba/fastjson2/issues_1800/Issue1819.java

@@ -0,0 +1,45 @@
+package com.alibaba.fastjson2.issues_1800;
+
+import org.apache.dubbo.common.URL;
+import org.apache.dubbo.common.serialize.ObjectInput;
+import org.apache.dubbo.common.serialize.ObjectOutput;
+import org.apache.dubbo.common.serialize.Serialization;
+import org.apache.dubbo.rpc.model.FrameworkModel;
+import org.junit.jupiter.api.Test;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class Issue1819 {
+    @Test
+    public void testWriteReadMap() throws Exception {
+        FrameworkModel frameworkModel = new FrameworkModel();
+        Serialization serialization = frameworkModel.getExtensionLoader(Serialization.class).getExtension("fastjson2");
+        URL url = URL.valueOf("").setScopeModel(frameworkModel);
+
+        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
+        ObjectOutput objectOutput = serialization.serialize(url, outputStream);
+        Map<String, Object> map = new HashMap<>();
+        List<Integer> workBysOrigin = new ArrayList<>();
+        workBysOrigin.add(120731003);
+        workBysOrigin.add(140707005);
+        map.put("work_by", workBysOrigin);
+        objectOutput.writeObject(map);
+        objectOutput.flushBuffer();
+
+        byte[] bytes = outputStream.toByteArray();
+        ByteArrayInputStream inputStream = new ByteArrayInputStream(bytes);
+        ObjectInput objectInput = serialization.deserialize(url, inputStream);
+        map = objectInput.readObject(Map.class);
+        List<Integer> workBys = (List) map.get("work_by");
+        for (int i = 0; i < workBys.size(); i++) {
+            assertEquals(workBysOrigin.get(i), workBys.get(i));
+        }
+    }
+}