This project is a REST API for payload register, exposed username, password and ip-address. The api validate the password and ip-address with spcific restrainctions. This project is built in java mavon with spring boot framework.

The project includes src and dependecies. In src section, the codes are in main and test sections.

1. $UserPayload.java$: This class represents the payload that your API will accept. It contains fields for the username, password, and IP address. Annotations such as @NotNull, @Size, and @Pattern are used for validation.
2. $UserController.java$: This class is your API controller. It handles incoming HTTP requests, validates the payload using the UserPayload class, interacts with the IP-API.com Geolocation API, and generates a response containing a UUID and a welcome message.
3. $GeolocationService.java$: (Optional) This service class abstracts the interaction with the IP-API.com Geolocation API. It's responsible for making the API request and processing the response.
4. $SwaggerConfig.java$: This configuration class sets up Swagger (OpenAPI) documentation for your API. It uses the Springfox library to generate API documentation that can be accessed through the Swagger UI.
5. $PayloadUserApplication.java$: This is the main class of your Spring Boot application. It contains the main method to start your application. It also serves as the entry point for Spring Boot's auto-configuration.

1. $UserControllerTest.java$: This JUnit test class tests the UserController class. It simulates requests to the API endpoints and verifies the responses, making sure that your API behaves as expected.
2. $UserPayloadTest.java$: This JUnit test class tests the UserPayload class by validating the payload's properties against defined constraints.
3. $PayloadUserApplicationTests.java$: This JUnit test class tests the main application class by checking whether the Spring context loads successfully. It ensures that the application's basic configuration is correct.

All dependencies are listed in file $pom.xml$.