Learn Kotlin step by step

1. Be sure JDK 11 installed.
2. Be sure gradle 6.x installed.
3. Be sure IntelliJ IDEA (CE) installed.
4. Be sure Kotlin Plugins of IDEA updated to the latest version(such as 1.4.10)
5. Create a file named init.gradle.kts under dir of $HOME/.gradle/, as

allprojects {
    repositories {
        maven {
            url = uri("http://**replace-me-with-your-nexus-server**:8081/repository/maven-public")
        }
        mavenCentral()
    }
}