What is the difference between Utility and Warranty?

Utility Warranty
The utility is defined as functionality offered by service or product from the customer perspective. Warranty is defined as a promise that service or product will agree with the need.
The utility deals with is what the client gets. Warranty deals with how service is delivered.
The utility should meet the customer requirement, that is, it should fit for the intention. Warranty should operate the service properly.
Utility can increases the performance average. Warranty can reduce performance variation.