Master Kotlin from basics to advanced features, building a strong foundation for Android and beyond
Dive into Kotlin: Modern, concise, and powerful
Kotlin is Google's preferred language for Android development. It's interoperable with Java, safer with null safety, and more expressive with functional features.
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Kotlin Basics and Syntax
Kotlin Basics and Syntax
Foundation concepts, basic syntax, and getting started with Kotlin
2 weeks
- play_circleKotlin Introduction and Setup (K2 compiler, IntelliJ/AS)
- play_circleVariables and Data Types
- play_circleval vs var and Immutability
- play_circleString Templates and Operations
- play_circleBasic Input/Output Operations
- play_circleComments and KDoc Basics
- articleKotlin vs Java (syntax & semantics quick tour)
- assignmentPractice: Basic Kotlin Programs
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Control Flow and Functions
Control Flow and Functions
Control structures, function declarations, and program flow
1.5 weeks
- play_circleif Expressions and when Statements
- play_circleLoops: for, while, do-while
- play_circleRanges and Progressions
- play_circleFunctions: parameters, defaults, named args
- play_circleSingle-Expression Functions
- articleReturn and Jump Expressions
- assignmentPractice: Control Flow Exercises
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Null Safety and the Type System
Null Safety and the Type System
Kotlin's null safety and core type-system features
1.5 weeks
- play_circleNullable vs Non-nullable Types
- play_circleSafe Calls, Elvis, and let
- play_circleNot-null Assertion (!!) - why to avoid it
- play_circleSmart Casts and is-checks
- play_circleScope Functions: run, with, apply, also
- play_circleType Checking & Casting, Nothing/Unit/Any quick tour
- articleNull-Safety Best Practices
- assignmentPractice: Null-Safety Implementation
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Object-Oriented Programming
Object-Oriented Programming
Classes, objects, inheritance, and OOP principles in Kotlin
2.5 weeks
- play_circleClasses and Objects Basics
- play_circlePrimary & Secondary Constructors; init
- play_circleProperties and Custom Accessors
- play_circleInheritance, open/final, and Overriding
- play_circleAbstract Classes and Interfaces (incl. sealed interfaces)
- play_circleVisibility Modifiers
- play_circleData Classes & Data Objects (Kotlin 1.9+)
- play_circleSealed Classes & Exhaustive when
- play_circleObject Declarations, Companion Objects
- articleNested and Inner Classes
- assignmentPractice: OOP Design Patterns
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Collections and Data Structures
Collections and Data Structures
Working with collections, sequences, and data manipulation
2 weeks
- play_circleArrays and Array Operations
- play_circleLists: Mutable vs Read-only
- play_circleSets and Maps Overview
- play_circleCollection Operations: filter/map/reduce
- play_circleSequences for Lazy Evaluation
- play_circleGrouping, Partitioning, Windowing
- play_circleSorting and Searching
- play_circleCustom Collection Operations
- articlePerformance Considerations & immutability tips
- assignmentPractice: Data Processing Pipeline
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Functional Programming
Functional Programming
Functional concepts, higher-order functions, and inline performance
2 weeks
- play_circleHigher-Order Functions & Function Types
- play_circleLambdas & Anonymous Functions (with receiver)
- play_circleClosures and Captured Variables
- play_circleinline/noinline/crossinline & performance
- play_circleFunction Composition & Partial Application
- play_circleTail Recursion (tailrec)
- articleFunctional Patterns in Kotlin (Option/Result style)
- assignmentPractice: FP Challenges
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Exception Handling and Error Management
Exception Handling and Error Management
Exceptions, Result type, and defensive programming
1 week
- play_circleException Hierarchy in Kotlin
- play_circletry/catch/finally Patterns
- play_circleThrowing & Custom Exceptions
- play_circleResult & runCatching; error mapping
- play_circleBest Practices (checked vs unchecked mindset)
- articleDefensive Programming Techniques
- assignmentPractice: Robust Error Handling
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Generics and Type Parameters
Generics and Type Parameters
Generic programming, constraints, and variance
1.5 weeks
- play_circleGeneric Classes and Functions
- play_circleType Parameters and where-Constraints
- play_circleVariance: in/out (use-site & declaration-site)
- play_circleStar Projections & Type Projections
- play_circleReified Type Parameters & inline
- play_circleType Inference tips & pitfalls
- articleBest Practices with Generics
- assignmentPractice: Generic Data Structures
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Coroutines and Async Programming (Language Intro)
Coroutines and Async Programming (Language Intro)
Language-level intro so you can read coroutine code; the full deep-dive is a separate course.
1 week
- play_circleCoroutines Fundamentals (suspend, builders, scopes)
- play_circleDispatchers & withContext (overview)
- play_circleFlows at a Glance (cold vs hot)
- articleExceptions & Cancellation - quick rules
- assignmentPractice: Async tasks with structured concurrency
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Advanced Language Features
Advanced Language Features
Modern Kotlin features you’ll actually use
2 weeks
- play_circleExtension Functions & Properties
- play_circleOperator Overloading (do’s & don’ts)
- play_circleDelegated Properties & patterns (lazy, observable, vetoable)
- play_circleType Aliases & Destructuring
- play_circleValue Classes (a.k.a. inline classes) + @JvmInline
- play_circleContracts (opt-in): callsInPlace, returns
- articleContext Parameters (replacing context receivers) - status & examples
- play_circleAnnotations & Annotation Processing (kapt/ksp overview)
- assignmentPractice: Advanced Feature Implementation
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DSL Creation and Metaprogramming
DSL Creation and Metaprogramming
Type-safe builders, receivers, and @DslMarker
1.5 weeks
- play_circleDSL Design Principles
- play_circleFunction Literals with Receiver
- play_circleType-Safe Builders & nested scopes
- play_circleDSL Scope Control with @DslMarker
- play_circleHTML/SQL DSL Examples
- articleDSL Testing & Docs
- assignmentPractice: Custom DSL Development
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Reflection and Runtime Features
Reflection and Runtime Features
Kotlin reflection API and runtime type info
1 week
- play_circleReflection Basics & KClass
- play_circleProperty & Function Reflection
- play_circleCallable References
- play_circleRuntime Annotation Processing (brief)
- play_circleReflection Performance & alternatives
- articleReflection Use Cases & pitfalls
- assignmentPractice: Reflection-Based Utilities
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Testing in Kotlin
Testing in Kotlin
Testing strategies and frameworks
1.5 weeks
- play_circleUnit Testing Fundamentals
- play_circleJUnit 5 with Kotlin
- play_circlekotlin.test & Assertions
- play_circleMocking with MockK
- play_circleProperty-Based Testing (Kotest/quickcheck)
- play_circleTesting Coroutines (pointer to the full course)
- articleTDD workflow in Kotlin
- assignmentPractice: Comprehensive Test Suite
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Best Practices and Code Quality
Best Practices and Code Quality
Conventions, performance, and professional practices
1 week
- play_circleKotlin Coding Conventions & Style
- play_circleStatic Analysis with Detekt & ktlint
- play_circlePerformance: allocations, boxing, inline/value classes
- play_circleMemory & GC basics (JVM/Native notes)
- play_circleOpt-in APIs: @RequiresOptIn / @OptIn and stability levels
- articleKotlin Evolution & K2 Migration Tips
- assignmentCapstone: Advanced Kotlin Application
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# Roadmap
