The Api response not match with sdk response.

Issue: Null Values Not Being Deserialized for Microsoft Graph API Responses via Java SDK

Description:

I am encountering an unexpected behavior when using the Microsoft Graph Java SDK to retrieve user data. Specifically, properties with null values in the API response are not being included in the deserialized object when using the SDK, while they are present when making a direct API call.

Detailed Scenario:

1. Direct API Call (e.g., Postman):
   When I make a direct GET request to the Microsoft Graph API (e.g., https://graph.microsoft.com/v1.0/me) using a tool like Postman, the JSON response includes all properties, even those with null values. For example, a response might contain:

   {
     "displayName": "John Doe",
     "jobTitle": null,
     "mobilePhone": "123-456-7890",
     "officeLocation": null,
     // ... other properties
   }
   

   In this example, jobTitle and officeLocation are explicitly present with null values.

2. Using Microsoft Graph Java SDK:
   I am using the microsoft-graph SDK (version 6.19.0) and have initialized a GraphServiceClient. When I perform a similar operation to retrieve user data (e.g., graphServiceClient.me().buildRequest().get()), and then attempt to access the deserialized User object, properties that had null values in the raw API response are seemingly filtered out or omitted during the deserialization process.

   After retrieving the User object and attempting to access its members, or after performing serialization of this SDK-generated object (especially when dealing with the Kiota-generated models and potentially abstracting the BackingStore layer), only the keys with non-null values are present. The properties that were null in the original API response are entirely absent from the deserialized User object's fields or when re-serializing the object.

Expected Behavior:

I expect the Microsoft Graph Java SDK's deserialization process to faithfully represent the entire API response, including properties that have null values. These null properties should be present in the deserialized User object, allowing me to differentiate between a property that is genuinely absent from the response and one that is explicitly present but with a null value.

Question/Request:

Is there any configuration or setting available within the Microsoft Graph Java SDK (or the underlying Kiota libraries) that allows for the deserialization of properties with null values, ensuring they are retained in the resulting Java objects? My goal is to prevent the implicit filtering of these null-valued keys.

SDK Version: :

• microsoft-graph version: [6.19.0]
• Java Version: [24.0.1]

首先使用 microsoft-graph 6.19.0 重现 GraphServiceClient.me().buildRequest().get() 的行为，将 Microsoft Graph 的直接响应与反序列化后的 User 对象及其重新序列化后的形式进行比较。然后检查 Kiota 生成的模型和 BackingStore 的行为，以确定是否可以区分显式为 null 的属性和不存在的属性。完成的标准是记录可用的配置，或确认 SDK 不会保留这种区别。