Cloud-Native Applications in Java

Validations and error messages

So far, we have been treading in very safe territory and assuming happy paths. But not everything will be right all the time. There are many scenarios such as:

1. GET, PUT, DELETE requests for products that don't exist.
2. PUT and POST missing critical information, for example, no product name or category.
3. Business validations, such as products, should belong to known categories and names should be more than 10 characters.
4. Incorrect formats of the data submitted, such as alphanumeric for category ID where only an integer was expected.

And these are not exhaustive. Therefore, it is always important to do validations and return appropriate error codes and messages when things go wrong.