(Kotlin vs. Java) What are the differences between Kotlin vs Java?

Kotlin vs Java - Android App Development

If you are a newbie Android developer and a little bit confused between Kotlin vs. Java, or if you don’t exactly know the differences between Kotlin vs Java, then this post is for you. Herein we have compared both the programming languages based on their features and functionalities, so you can have a look at the comparison and decide which language has advanced features for Android development.

If you are a newbie in the Android app development world, then the only language that you, as an Android developer, can think of is, Java and that is quite obvious. The reason behind this is – Java exists in the market for the past many years and most of the Android apps are developed in Java. 

But these days, you might be hearing a lot about Kotlin that is Google’s official programming language for writing Android apps. And there are many companies like Amazon, Netflix, and Pinterest that showed their interest in this programing language. In fact, many apps like Pinterest, Evernote, Postmates, Uber are developed in Kotlin language. 

As a beginner Android app developer, you might think which language is more useful and why. What are the unique features of Kotlin programming language that are not available in Java? To give answers to common questions of amateur Android developers, we decided to compare Kotlin vs. Java features in this blog. 

So, you can go through this blog and identify it on your own that which language is more useful for your next Android app project. To make it easy, we have also prepared Kotlin vs. Java infographic that will give you a quick look into comparison. However, you can go through the in-detailed comparison of Kotlin and Java features in the given table. So, let’s first check out Kotlin vs. Java infographic:

Kotlin vs. Java Infographic

Kotlin vs Java

Comparison Table on Kotlin vs. Java

In this table, you can get a detailed comparison of Kotlin and Java features that will help you to understand the difference between both the programming languages.

Sr. no. Features Kotlin Java
1 Extension functions Available in Kotlin. Extensions are useful as they allow developers to
add methods to classes without making changes to their source code.
In Java, we need to create a new class to extend the functionality of the existing class, so from now users can use a newly created class everywhere to use the extended functionality.
2 Null safety Available. Kotlin’s type of system has inbuilt null safety. Not available. In fact, NullPointerException is mainly responsible for the development errors of Android and Java.
3 Static members In Kotlin, we can use the companion object to create static members of the class.
An object declaration inside a class can be marked with the companion keyword.
Available in Java. It is used for memory management mainly. One can apply java static keyword with variables, methods, blocks and nested class.
4 String templates Yes, there are two types of string literals in Kotlin such as escaped string and raw string.
Kotlin string template also supports expression.
Available in Java too, but it doesn’t support expression like Kotlin.
5 Coroutines In Kotlin, coroutines are concurrency design pattern.
It can be used to simplify code on Android that performs asynchronously.
Coroutines were added to Kotlin in 1.3 version and
they are based on established concepts from other languages.
In Java, users have two different options such as RxJava and Project Loom.
RxJava is a library for composing asynchronous and event-based programs using observable sequences and Project Loom supports a high-throughput, lightweight concurrency model in Java.
6 Wildcard-types No, Kotlin doesn’t have any wildcard-types.
But it has two other things, including declaration-site variance and type projections.
Available in Java. Wildcard in general code means (?) that represents an unknown type.
It can be used in different situations.
7 Smart casts Yes, this feature is available in Kotlin.
It helps Kotlin compiler to track conditions inside if expression.
If the compiler finds a variable that is not null of type nullable, the compiler allows accessing the variable.
No, it is not available in Java.
However, to know the types in Java, we can use something like instance of to check the type and then cast it to the right type.
8 Lazy-Loading Yes, it is available in Kotlin.
It mainly decreased startup time that is useful when using Kotlin for app development.
This feature is not available in Java.
9 No checked exceptions Kotlin removed exceptions entirely in order to minimize verbosity and improve type-safety. In Java, the checked exceptions feature is a problem as it causes empty catch blocks.
10 Operator overloading Yes, Kotlin allows users to provide a way to invoke functions.
It allows to do an arithmetic operation, equality checks or comparison on whatever object we want, through symbols like +, -, /, *, %, <, >.
In Java, operators are tied to particular Java types.
For instance, String and numeric types in Java can make use of + operator for concatenation and addition. Another Java type can’t reuse this operator.


Herein we discussed and compared the major points of Kotlin and Java languages. And we hope that this comparison helps you, as an Android developer, to understand the difference and decide which language is more preferable to developing Android apps.

However, if you have already started using Kotlin over the Java language, you can share your experience and features that we have not covered here in this table. Share your views in the comment section.

In any case, if you still have any confusion about whether to use Kotlin or Java for Android application development, what are the benefits of choosing Kotlin over Java, how to hire developers with expertise in Kotlin, get in touch with us through our contact us form. One of our sales representatives will comprehend your app development project and suggest the right language to choose from.


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