Unable to implement PUT request in angular 2 ,gett

Question

I have implemented GET request in my application and able to fetch data for my Account Table in the AccountComponent.

When I click on a particular row in the DataGrid , I get a POPUP window where I can access the row_data and using the dropdowns can update the **DataGrid **

But when I am selecting the required values for the dropdowns and trying to update, I'm getting the following error in my console.

Error code is : Error {"message":"Null values are not allowed","error":"java.lang.NullPointerException","path":"/spacestudy/rockefeller/admin/account/saveAttributes"}

Please access my sample StackBlitz here

Below shown are the screenshots of my sample app.

This is my Account Table

When I click on a row here is my POPUP

When I try to update I'm getting the following error in my console & Network tab

But when I'm trying to save it from backend through Swagger UI,then I'm able to successfully update the data

Can anybody please help me to solve this issue....?

Latest screen shot