kotlin-fundamentals

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Kotlin language fundamentals - syntax, null safety, data classes, extensions

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Added on2026-02-22

NPX Install

npx skill4agent add pluginagentmarketplace/custom-plugin-kotlin kotlin-fundamentals

Master Kotlin programming fundamentals with production-ready patterns.

kotlin

// Safe call + Elvis
val name = user?.name ?: "Anonymous"

// requireNotNull for validation
requireNotNull(user) { "User required" }

kotlin

data class User(val id: Long, val name: String) {
    init { require(name.isNotBlank()) }
}

Function	Context	Returns	Use Case
`let`	it	Lambda result	Null-safe transforms
`apply`	this	Same object	Object configuration
`run`	this	Lambda result	Object scope + result
`also`	it	Same object	Side effects

Issue	Resolution
NPE despite null check	Check platform types from Java
Smart cast fails	Use local variable or let

Skill("kotlin-fundamentals")