Annotations in Kotlin

// Annotation declaration
@Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION)
@Retention(AnnotationRetention.RUNTIME)
@MustBeDocumented
annotation class MyAnnotation(
    val name: String,
    val version: Int = 1
)

// Using annotations
@MyAnnotation(name = "Example", version = 2)
class AnnotatedClass {
    @Deprecated("Use newMethod instead")
    fun oldMethod() {}

    @JvmStatic
    fun staticMethod() {}

    @Throws(IOException::class)
    fun riskyMethod() {
        throw IOException("Error")
    }
}

// Built-in annotations
class Example {
    @JvmField
    val field = "Public field in Java"

    @JvmOverloads
    fun method(a: String = "default") {}

    @Suppress("UNCHECKED_CAST")
    fun uncheckedCast(obj: Any): List<String> {
        return obj as List<String>
    }
}