bug fixed for PrettyFormat, fix #3672

src/main/java/com/alibaba/fastjson/serializer/ObjectArrayCodec.java

@@ -75,7 +75,7 @@ public final void write(JSONSerializer serializer, Object object, Object fieldNa
                         out.write(',');
                         serializer.println();
                     }
-                    serializer.write(array[i]);
+                    serializer.writeWithFieldName(array[i], Integer.valueOf(i));
                 }
                 serializer.decrementIdent();
                 serializer.println();

src/test/java/com/alibaba/json/bvt/issue_3600/Issue3672.java

@@ -0,0 +1,59 @@
+package com.alibaba.json.bvt.issue_3600;
+
+import com.alibaba.fastjson.JSON;
+import com.alibaba.fastjson.JSONObject;
+import com.alibaba.fastjson.serializer.SerializerFeature;
+import com.google.common.collect.Lists;
+import lombok.Data;
+import org.junit.Test;
+
+import java.util.ArrayList;
+
+import junit.framework.TestCase;
+
+public class Issue3672 extends TestCase {
+    public void test_for_issue() throws Exception {
+        Issue3672Root root = new Issue3672Root();
+        Issue3672A a = new Issue3672A();
+        Issue3672B b = new Issue3672B();
+        Issue3672C c = new Issue3672C();
+        Issue3672D d = new Issue3672D();
+        root.setA(a);
+        a.setB(Lists.newArrayList(b).toArray());
+        b.setC(c);
+        c.setD(d);
+        d.setE(Lists.newArrayList(c));
+        String str1 = JSON.toJSONString(root, SerializerFeature.PrettyFormat, SerializerFeature.WriteMapNullValue);
+        String str2 = JSON.toJSONString(root);
+
+        JSONObject obj1 = JSON.parseObject(str1);
+        JSONObject obj2 = JSON.parseObject(str2);
+        assertEquals(obj1.toString(), obj2.toString());
+    }
+
+    @Data
+    private class Issue3672Root {
+        private Issue3672A a;
+    }
+
+    @Data
+    private class Issue3672A {
+        private Object[] b;
+    }
+
+    @Data
+    private class Issue3672B {
+        private Issue3672C c;
+    }
+
+    @Data
+    private class Issue3672C {
+        private Issue3672D d;
+    }
+
+    @Data
+    private class Issue3672D {
+        private ArrayList<Issue3672C> e;
+    }
+
+}