mvn spotless

java/fury-core/src/main/java/org/apache/fury/Fury.java

@@ -462,6 +462,29 @@ public <T> void writeRef(MemoryBuffer buffer, T obj, Serializer<T> serializer) {
     }
   }
 
+  public <T> void writeRefNullable(
+      MemoryBuffer buffer, T obj, Serializer<T> serializer, boolean nullable) {
+    if (serializer.needToWriteRef()) {
+      if (!refResolver.writeRefOrNull(buffer, obj)) {
+        depth++;
+        serializer.write(buffer, obj);
+        depth--;
+      }
+    } else {
+      if (nullable) {
+        if (obj == null) {
+          buffer.writeByte(Fury.NULL_FLAG);
+          return;
+        } else {
+          buffer.writeByte(Fury.NOT_NULL_VALUE_FLAG);
+        }
+      }
+      depth++;
+      serializer.write(buffer, obj);
+      depth--;
+    }
+  }
+
   /** Write object class and data without tracking ref. */
   public void writeNullable(MemoryBuffer buffer, Object obj) {
     if (obj == null) {
@@ -961,6 +984,29 @@ public <T> T readRef(MemoryBuffer buffer, Serializer<T> serializer) {
     }
   }
 
+  @SuppressWarnings("unchecked")
+  public <T> T readRefNullable(MemoryBuffer buffer, Serializer<T> serializer, boolean nullable) {
+    if (serializer.needToWriteRef()) {
+      T obj;
+      int nextReadRefId = refResolver.tryPreserveRefId(buffer);
+      if (nextReadRefId >= NOT_NULL_VALUE_FLAG) {
+        obj = serializer.read(buffer);
+        refResolver.setReadObject(nextReadRefId, obj);
+        return obj;
+      } else {
+        return (T) refResolver.getReadObject();
+      }
+    } else {
+      if (nullable) {
+        byte headFlag = buffer.readByte();
+        if (headFlag == Fury.NULL_FLAG) {
+          return null;
+        }
+      }
+      return serializer.read(buffer);
+    }
+  }
+
   /** Deserialize not-null and non-reference object from <code>buffer</code>. */
   public Object readNonRef(MemoryBuffer buffer) {
     return readDataInternal(buffer, classResolver.readClassInfo(buffer));

java/fury-core/src/main/java/org/apache/fury/serializer/CompatibleSerializer.java

@@ -141,7 +141,8 @@ private void readAndWriteFieldValue(
         } else {
           ClassInfo classInfo = fieldInfo.getClassInfo(classId);
           Serializer<Object> serializer = classInfo.getSerializer();
-          fury.writeRef(buffer, fieldValue, serializer);
+          fury.writeRefNullable(
+              buffer, fieldValue, serializer, fieldInfo.getFuryFieldAnnotationInfo().nullable);
         }
       }
     }
@@ -181,7 +182,8 @@ private void writeFieldValue(
         buffer.writeFloat64((Double) fieldValue);
         return;
       case ClassResolver.STRING_CLASS_ID:
-        fury.writeJavaStringRef(buffer, (String) fieldValue);
+        fury.writeJavaStringRef(
+            buffer, (String) fieldValue, fieldInfo.getFuryFieldAnnotationInfo().nullable);
         break;
       case ClassResolver.NO_CLASS_ID: // SEPARATE_TYPES_HASH
         writeSeparateFieldValue(fieldInfo, buffer, fieldValue);
@@ -190,7 +192,8 @@ private void writeFieldValue(
         {
           ClassInfo classInfo = fieldInfo.getClassInfo(classId);
           Serializer<Object> serializer = classInfo.getSerializer();
-          fury.writeRef(buffer, fieldValue, serializer);
+          fury.writeRefNullable(
+              buffer, fieldValue, serializer, fieldInfo.getFuryFieldAnnotationInfo().nullable);
         }
     }
   }
@@ -580,7 +583,10 @@ private void readAndSetFieldValue(
       } else {
         ClassInfo classInfo = fieldInfo.getClassInfo(classId);
         Serializer<Object> serializer = classInfo.getSerializer();
-        fieldAccessor.putObject(targetObject, fury.readRef(buffer, serializer));
+        fieldAccessor.putObject(
+            targetObject,
+            fury.readRefNullable(
+                buffer, serializer, fieldInfo.getFuryFieldAnnotationInfo().nullable));
       }
     }
   }
@@ -610,14 +616,15 @@ private Object readFieldValue(FieldResolver.FieldInfo fieldInfo, MemoryBuffer bu
       case ClassResolver.PRIMITIVE_DOUBLE_CLASS_ID:
         return buffer.readFloat64();
       case ClassResolver.STRING_CLASS_ID:
-        return fury.readJavaStringRef(buffer);
+        return fury.readJavaStringRef(buffer, fieldInfo.getFuryFieldAnnotationInfo().nullable);
       case ClassResolver.NO_CLASS_ID:
         return fieldResolver.readObjectField(buffer, fieldInfo);
       default:
         {
           ClassInfo classInfo = fieldInfo.getClassInfo(classId);
           Serializer<Object> serializer = classInfo.getSerializer();
-          return fury.readRef(buffer, serializer);
+          return fury.readRefNullable(
+              buffer, serializer, fieldInfo.getFuryFieldAnnotationInfo().nullable);
         }
     }
   }