Spring Boot RESTful web service JSON example

Spring Boot comes with all the needed components for creating RESTful web services. Here we will see how easily we can build a simple Spring Boot application which will provide web services for CRUD operations i.e. Create, Retrieve, Update and Delete operations using HTTP POST, GET, PUT and DELETE method respectively. To keep the application simple, we will not use any database. Instead just use a HashMap to store the data objects through a Service layer class.