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Kotlin

Information Technology > Programming languages

Description

Kotlin is a modern programming language that combines object-oriented and functional programming features. It's statically typed, meaning the type of each variable is known at compile time, enhancing code safety and predictability. Kotlin offers concise syntax, making it easier to read and write code. It includes advanced features like coroutines for handling asynchronous tasks, extension functions for adding new functionalities to existing classes, and null safety to eliminate the risk of null reference exceptions. It's interoperable with Java and other JVM languages, allowing developers to use existing libraries and frameworks. Kotlin is widely used for Android app development and is also gaining popularity in backend development.

Expected Behaviors

✎
LEVEL 1

Fundamental Awareness

At this level, individuals are expected to have a basic understanding of Kotlin's syntax, data types, variables, and control flow statements. They should also be familiar with the concept of null safety in Kotlin, which helps prevent runtime nullability errors.

🌱
LEVEL 2

Novice

Novices should be able to write simple functions, understand the concepts of classes and objects, and handle exceptions. They should also have knowledge of collections and arrays, and be able to perform basic input/output operations.

🌍
LEVEL 3

Intermediate

Intermediate users should be proficient in using standard library functions and understand generics. They should be able to use lambdas and higher-order functions, know how to use extension functions, and understand file handling.

⭐
LEVEL 4

Advanced

Advanced users should be proficient in using coroutines for asynchronous programming and understand advanced features like sealed classes, inline classes, and type aliases. They should be able to create and use custom DSLs, understand reflection and annotations, and have a grasp on multi-threading and concurrency.

🏆
LEVEL 5

Expert

Experts should be proficient in using advanced libraries and frameworks like Ktor, Arrow, etc. They should understand Kotlin/Native and Kotlin/JS, be able to optimize code for performance, have knowledge of interoperability with Java and other JVM languages, and understand advanced concepts like metaprogramming and type systems.

Micro Skills

✎
LEVEL 1

Fundamental Awareness

Knowledge of Kotlin keywords
Understanding of expressions and statements
Familiarity with comments and whitespace
Ability to declare variables and constants
Understanding of basic data types (Int, Double, Boolean, String)
Ability to declare and initialize variables
Understanding of type inference
Knowledge of nullability and nullable types
Understanding of conditional statements (if, when)
Ability to use loops (for, while)
Knowledge of how to use break and continue
Understanding of the concept of nullability
Knowledge of safe calls and the Elvis operator
Ability to use non-null assertions
Understanding of safe casts
🌱
LEVEL 2

Novice

Understanding of function syntax
Knowledge of function parameters and return types
Ability to use default and named arguments
Understanding of recursion
Knowledge of class declaration and instantiation
Understanding of properties and methods
Familiarity with constructors
Understanding of inheritance and interfaces
Understanding of different collection types (List, Set, Map)
Ability to perform operations on collections (filtering, mapping, reducing)
Knowledge of array declaration and manipulation
Understanding of try/catch blocks
Knowledge of different exception types
Ability to throw and create custom exceptions
Ability to read from and write to the console
Understanding of file I/O operations
Knowledge of reading from and writing to network sockets
🌍
LEVEL 3

Intermediate

Ability to use filter, map, reduce, and other transformation functions
Knowledge of grouping, sorting, and other ordering functions
Understanding of set operations like union, intersection, and difference
Ability to use functions for string concatenation, splitting, and trimming
Understanding of regular expressions and pattern matching
Knowledge of string interpolation and formatting
Understanding of basic arithmetic functions
Knowledge of functions for rounding, absolute value, and sign
Ability to use trigonometric and logarithmic functions
Ability to get current date and time
Understanding of date and time formatting and parsing
Knowledge of date and time arithmetic
Understanding of type parameters in classes and interfaces
Knowledge of type parameters in functions
Ability to use generic constraints
Knowledge of declaration-site variance
Understanding of use-site variance
Ability to use star-projections
Understanding of function types
Knowledge of invoking functions with function parameters
Ability to return functions from functions
Ability to use function references
Understanding of bound function references
Knowledge of callable references to constructors or property accessors
Understanding of how to declare extension functions
Knowledge of how to call extension functions
Ability to use extension functions in combination with other language features
Ability to declare extension properties
Knowledge of how to use extension properties
Understanding of limitations of extension properties
Understanding of how to open a file for reading or writing
Knowledge of how to read from or write to a file
Ability to handle file-related exceptions
Ability to create a buffered reader or writer
Knowledge of how to read from or write to a buffer
Understanding of when to use buffering
Ability to perform basic file operations
Understanding of how to handle errors during file operations
Knowledge of how to check the result of a file operation
⭐
LEVEL 4

Advanced

Knowledge of how to define suspend functions
Understanding of how suspension works
Ability to use suspend functions in coroutines
Understanding of the difference between launch and async
Ability to use launch for fire-and-forget tasks
Knowledge of using async for computationally intensive tasks
Understanding of CoroutineExceptionHandler
Knowledge of try/catch blocks in coroutines
Ability to use supervisor jobs and scopes
Knowledge of different dispatchers
Understanding of how to switch context
Ability to create custom contexts
Understanding of how to cancel a coroutine
Knowledge of cooperative cancellation
Ability to use withTimeout function
Understanding of when to use sealed classes
Knowledge of how to define a sealed class
Ability to use sealed classes in when expressions
Knowledge of the benefits of inline classes
Understanding of how to define an inline class
Ability to use inline classes in code
Understanding of when to use type aliases
Knowledge of how to define a type alias
Ability to use type aliases in code
Knowledge of what a DSL is
Understanding of the benefits of DSLs
Ability to identify examples of DSLs
Understanding of how to define a DSL function
Knowledge of how to use lambda with receiver in DSLs
Ability to create a simple DSL
Understanding of how to add functions to a DSL
Knowledge of how to use extension functions in DSLs
Ability to modify an existing DSL
Knowledge of what a receiver is
Understanding of how to use lambda with receiver
Ability to use receivers in DSLs
Knowledge of KClass, KFunction, etc.
Understanding of how to get class information
Ability to call functions and access properties reflectively
Understanding of built-in annotations
Knowledge of how to apply annotations
Ability to use annotation arguments
Understanding of how to define an annotation
Knowledge of annotation targets and retention
Ability to use custom annotations in code
Knowledge of how annotation processing works
Understanding of how to write an annotation processor
Ability to use annotation processors in build process
Understanding of how to create a thread
Knowledge of how to implement Runnable
Ability to start and stop threads
Knowledge of synchronized keyword
Understanding of intrinsic locks
Ability to use explicit locks
Understanding of ConcurrentHashMap, ConcurrentLinkedQueue, etc.
Knowledge of atomic variables
Ability to use concurrent collections in multi-threaded code
Understanding of wait/notify mechanism
Knowledge of BlockingQueue
Ability to use Exchanger and Phaser
Knowledge of ExecutorService and ScheduledExecutorService
Understanding of how to submit tasks to executor
Ability to manage thread pool size and handle rejected tasks
🏆
LEVEL 5

Expert

Knowledge of Ktor's modular architecture
Ability to configure Ktor applications
Understanding of routing in Ktor
Ability to handle requests and responses
Understanding of functors, applicatives, and monads
Ability to use Arrow's type classes
Understanding of optics in Arrow
Ability to use Arrow's data types for asynchronous programming
Understanding of platform-specific features and limitations
Ability to write multiplatform code
Understanding of Gradle configuration for Kotlin/Native and Kotlin/JS
Ability to debug and test Kotlin/Native and Kotlin/JS code
Knowledge of bytecode generation and JIT compilation
Understanding of Kotlin's runtime library
Understanding of profiling tools and techniques
Ability to optimize memory usage and CPU time
Knowledge of how Java classes and methods are represented in Kotlin
Ability to call Java code from Kotlin and vice versa
Understanding of inline functions and reified types
Ability to use Kotlin's reflection API
Understanding of variance annotations
Ability to use sealed classes and when expressions

Skill Overview

  • Expert2 years experience
  • Micro-skills156
  • Roles requiring skill0

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