Learn Kotlin syntax

Declare read-only variables using 'val' and mutable variables using 'var', and explain how Kotlin's type inference simplifies declaration.

Apply the not-null assertion operator (!!) and explain the risk of a NullPointerException.

Configure a new Spring Boot project to use Kotlin.

Convert a Java-based Spring @RestController to its idiomatic Kotlin equivalent.

Define a Spring Data JPA entity using a Kotlin `data class` with `var` properties and a no-arg constructor for JPA compatibility.

Implement a Spring @Service that uses Kotlin's null-safety features to handle optional results from a repository.

Write a unit test for a Kotlin Spring component using JUnit 5 and Mockito.