Implementing a REST service using Kotlin

We will start with creating a service returning a hardcoded string. After that, we will discuss an example returning a proper JSON response. We will also look at an example of passing a path parameter.

Simple method returning a string

Let's start with creating a simple REST service returning a welcome message:

    @RestController
    class BasicController {
      @GetMapping("/welcome")
      fun welcome() = "Hello World"
    }

A comparable Java method is shown as follows. A major difference is how we are able to define a function in one line in Kotlin--fun welcome() = "Hello World":

    @GetMapping("/welcome")
    public String welcome() {
  ...