Everything You Need to Know About Kotlin Programming Language by Google 
                      Everything You Need to Know About Kotlin Programming Language 
by Google

Kotlin has been gaining popularity worldwide for a variety of reasons. The 
language has skyrocketed tremendously since its launch and quickly joined 
the ranks of the most popular programming languages. Now that Google 
supports Kotlin for Android app development over Java, it has become one of 
the most sought after programming languages among developers.
Per the PYPL Popularity of Programming Language Index, Kotlin is ranked 
among the top 15 best programming languages in September 2020 
worldwide. Additionally, according to JetBrains, Kotlin is among the top 3 
languages developers are planning to adopt or migrate to. Considering this, 
many businesses are seeking a skilled kotlin application development 
company  that can develop a revenue-driven app and help them gain a 
competitive advantage.
What Is Kotlin?
At Google I/O 2017, Google announced that it would start supporting a new 
Android development language: Kotlin. It is an open-source, statically typed 
programming language that can transpile Java bytecode to run on the Java 
Virtual Machine (JVM) or Android, combining object-oriented and functional 
programming features.
Kotlin is developed by JetBrains, a company behind the IntelliJ Java IDE that 
Android Studio is based on. They designed Kotlin to be 100% interoperable 
with Java, allowing developers to use any Java libraries and frameworks in 
Kotlin, and vice-versa.
Top Popular Apps/Companies Using Kotlin
Is Kotlin a new era of Android app development? This question often arises 
as within a year of launch, Kotlin has been trending as a top-class 
replacement of Java for Android development. Over 60% of Android 
developers are now using Kotlin, becoming the fastest-growing language on 
GitHub in terms of the number of contributors. Some of the world’s most 
popular apps are built with Kotlin:
• Google
• Pinterest
• Square
• Trello
• Evernote
• Slack
• Corda
• Tinder
• N26
• Netflix
• Airbnb
• Basecmp
What Is Kotlin Used For?
Being a general-purpose programming language, Kotlin can be applied in 
various ways, for cross-platform mobile, Android, JavaScript, and server-side 
development. Kotlin also lets developers use popular libraries and 
frameworks such as ReactJS and VueJS.
Today, it is most prominently used for Android development. Let’s look 
at the corresponding sub-projects of Kotlin:
• Kotlin/JVM: Enables writing JVM applications by transpiling to 
Java bytecode. For example -Android development, Spring 
services, and desktop applications.
• Kotlin/JS: Allows writing web applications by transpiling to 
JavaScript. For example, – React apps and Vanilla JS apps.
• Kotlin/Native: Enables writing applications for embedded 
devices or iOS development. For example – iOS apps, 
microcontroller programming, and others.
Kotlin supports multi-platform application development, which enables 
you to share code between apps for different platforms. The most 
obvious use case is to share core functionality between the Kotlin 
Android app and the Kotlin iOS app.
Kotlin Language and Syntax
In terms of language and syntax, Kotlin simply aims to be readable, 
pragmatic, and safe. To fully appreciate what that means, let’s take a 
look at the language’s core tenets.
• Readability – Kotlin is supported by language features such as 
type inference, data classes, and infix functions. Such features 
enable concise code without sacrificing readability.
• Pragmatism – JetBrains themselves use it to develop their 
IDEs. Kotlin incorporates industry feedback and addresses large-
scale app development issues, crucial for the large-scale 
enterprise app development Kotlin is frequently used for 
JetBrains itself uses it to develop its IDEs.
• Safety – Kotlin aims to prevent common app bugs by design. 
This is accomplished through several language features such as 
nullable types (to avoid null pointer exceptions) and nudging 
towards the best practices like designing for inheritance.
Why Do Developers Prefer Kotlin Over Any Other Language?
Why has Kotlin created such a buzz? Why do many developers love 
it? Why should one choose Kotlin over others? We decided to 
handpick several answers to all of those questions. Let’s dive in and 
learn!
Open-Source
Kotlin was introduced with the need for more concise language 
compatible with Java and JavaScript in mind. Instead of keeping it as 
an internal project, JetBrains decided to open-source it in 2012. Since 
then, satisfied developers have sparked Kotlin’s meteoric rise through 
the app development world.
Lesser Code Writing
Java requires detailed code writing; the Kotlin compiler, on the other 
hand, can understand code and write a lot of code itself with ease. It is 
believed that developers can write 20% less code in Kotlin, drastically 
reducing boilerplate code. As a result, developers can spend more 
time on the exciting parts of the coding, leaving Kotlin to manage the 
routine code itself.
Backed by Google
Perhaps the most appealing thing about Kotlin language is that 
Google backs it. Google’s support gave life to Kotlin when it declared 
Kotlin to be the officially supported language for Android at its I/O 
annual summit 2017. With Google’s announcement, many prior fears, 
such as bugs, unsupported formats, and others, were laid to rest, and 
developers can now freely develop apps using Kotlin.
100% Interoperability with Java
Kotlin and Java are two similar languages that can, fortunately, go 
hand-in-hand. Kotlin has 100% interoperability with Java, meaning 
developers can have any percentage of code written in Kotlin, and the 
rest in Java. If developers have the codes from both Java and Kotlin in 
the same project, they can compile correctly. In short, if developers 
are working with Kotlin, they get the benefit of vast Java commands, 
Java libraries, and Java frameworks.
Object-Oriented and Functional Language
Being both object-oriented and functional constructs, Kotlin wins over 
other languages, which means it can be used in object-oriented and 
functional programming styles, offering developers great features like 
high-order functions, function types, and lambdas to explore functional 
programming.
Server-Side Development
Kotlin is not only used for Android development but server-side 
developments as well. With 100% compatibility with JVMwhile 
maintaining full compatibility with existing Java-based technology 
stacks, developers can leverage server-side development using 
Spring and Vert frameworks.x, Ktor, Kotlinx.html, and more.
Null Safety
One of the best features of Kotlin is that there is no 
NullPointerException. With Kotlin, developers don’t need to worry 
about NPEs because null safety is built into Kotlin’s type system. The 
Kotlin system refuses to compile code that tries to assign or return 
null, so developers can catch NPEs at compile time instead of 
runtime, and eliminate the danger of null references from code.
Use of Existing Java Frameworks and Libraries
Kotlin can readily use all existing Java frameworks and libraries. Kotlin 
programs can use all advanced frameworks too, which rely on 
annotation processing. Kotlin is an easy-to-integrate language and is 
frequently integrated with Gradle, Maven, and other build systems.
Extension Functions
It is easy to compose functions in Kotlin with extensions and 
operators. As in C# and Gosu, Kotlin gives developers the ability to 
extend a class with new functionality without inheriting the class or 
using any design pattern like Decorator. Extension functions help 
developers to extend the functionalities of classes without touching the 
core code.
Great IDE and Tooling Support
Kotlin’s excellent support is backed by JetBrains, a company that’s 
created some of the world’s most used IDEs. With a strong community 
behind Kotlin’s language and tools, developers can always have 
support when they need it. Additionally, all of Android Studio’s IDE 
features work perfectly in Kotlin.
Kotlin vs Java
For many years, Java was the only programming language for Android 
and server-side development. However, the launch and rise of Kotlin 
have changed Java’s dominant position. Let’s take a look at how the 
two heavyweights stack up against each other.
Size, Complexity, and Code Quality
Java requires more code lines, while Kotlin enables developers to 
accomplish the same tasks with lesser code, making it more 
expressive. This helps developers make code more organized, 
readable, and reusable, thus lessening their efforts and increasing 
productivity. To help manage the quality of code, Kotlin uses type 
inferencing, eliminating overly tedious syntax that Java developers 
face.
No NullPointerException
Built-in null safety makes Kotlin an obvious leader when it comes to 
Android development. NullPointerException is one of the major 
causes of Android mistakes as Java enables developers to assign a 
null value to an object reference, resulting in Android apps’ crash. 
Kotlin, on the other hand, offers inherent null safety, which means no 
variable or object can be assigned with a null value.
Interoperability
Interoperability is probably one of the most attractive features of 
Kotlin. Being 100% interoperable with Java allows writing some parts 
of code that work seamlessly within Java code, making it much easier 
to switch from Java to Kotlin during development.
Coroutine Support
Whenever developers start a long-running process with CPU intensive 
operations in Java, the corresponding thread gets blocked. It is 
possible to create multiple threads but managing them is complex. 
With Coroutine support, however, developers can create multiple 
threads to run long processes in Kotlin without thread blocking.
Delegation
Java lacks this feature, which makes Kotlin superior in terms of using 
multiple inheritances. Kotlin allows for a receiving object to delegate 
operations to a second delegate object, called the helper object, 
containing original content so that developers don’t need to rewrite it. 
The multiple inheritances avoid the duplication of code.
Compile Time and Performance
Talking about performance, Kotlin runs as fast as Java. However, the 
support of inline functions and the use of lambdas allow developers to 
create apps that run faster than Java code. Java compiles 10-15% 
faster than its counter partner in clean builds; however, Kotlin works 
slightly better, thus better handling functional programming.
Functional Programming
Java supports functional programming, but only in Java 8, whereas 
most Android development is done with Java 6 and 7. Kotlin is a mix 
of functional, procedural programming, which consists of many useful 
methods like lambdas, higher-order functions, lazy evaluation, and 
more; most of these methods are not offered for Android developers in 
Java 8.
Conclusion
Kotlin is safer, stabler, more reliable, and faster, eliminating null 
reference errors, enabling extension functions, supporting functional 
programming, and adding coroutines. With big market players like 
Google, Netflix, Pinterest, Evernote, Airbnb, and Trello using Kotlin, it’s 
no wonder why both developers and companies are gravitating to 
Kotlin in droves.