Getting null values in postman while fetching data from database although data is present in database using springboot

I am trying to create a blog apis but Getting null values in postman while fetching data from database although data is present in database using springboot, when i am trying to get data by userId or categoryId. it's giving me null value as shown. { "postTitle": null, "postContent": null, "postImageName": null, "postAddedDate": null, "category": null, "user": null }