Kotlin vs java Which One Is Better

Kotlin vs Java Which One Is Better? Details and Comparison

Android developers know that the main languages which are used to develop Android applications are Java and Kotlin languages. But, after Kotlin’s first stable release on 15 February 2016, developers started to adapt Kotlin for Android application development. Also, in May 2017 Google announced that Kotlin is Google’s preferred language for Android application developers. So let’s have a look at both languages Kotlin vs java and Which One Is Better? and compare Kotlin vs Java performance.



James Gosling at Sun Microsystems originally developed the Java language. It first released in 1995. Java is a class-based, general-purpose object-oriented language. Java code runs on any platform that supports Java. It does not need any recompilation.


Kotlin is a statically typed programming language. Because it is a general-purpose programming language. It is completely interoperable with Java and JVM. It is designed in such a way that not only it is interoperable with Java but also helps developers in migrating from Java to Kotlin.


Which Language is Better? Java or Kotlin

Java is considered one of the best languages for developers. It has a huge number of developers as well. In 2019 there were around 8 million developers using Java as the main language. But, no doubt there are a lot of things that Java does not offer but Kotlin does. Here is a quick comparison between both languages.


Kotlin vs java Which One Is Better
Kotlin vs java Which One Is Better


Code Conciseness

Code conciseness is the main feature in Kotlin. If we compare a Java class with a Kotlin class then we find that Kotlin reduces the amount of code. That means a 10 line Java code becomes a 4 to 5 lines code in Kotlin.

The main thing is Java needs a reference of the view into the Activity using the findViewbyId() method. Due to Kotlin’s  Android Extension, we do not need to import the reference of the View into the Activity file. It allows working with Views as they are part of the same Activity.

Data Classes

In projects, developers use a lot of classes that hold data. So it needs to write a lot of code in Java. It needs constructor, fields then setter and getter for every field and other related functions. Kotlin deals with these classes very smartly. The only thing you have to do is to add the “data” keyword before the class name. So the compiler will handle other things on its own.

Checked Exceptions

Checked exception features can create many problems for developers. This happens when the caller of any function is forced by the compiler to catch or re-throw an exception. They cause empty catch blocks and unnecessary exceptions most of the time. Empty catch blocks are a real trouble maker for developers because developers need to check the entire code to identify a nonexistent exception. Kotlin reacts here smartly and entirely removes these exceptions. It saves code from errors and helps to improve type-safety.


Kotlin vs java Which One Is Better
Kotlin vs java Which One Is Better


Android is single-threaded by default. If the main thread is blocked then it freezes the UI. To run long-running operations in Java we create a background thread. But, the problem is when more than one thread works it may lead to errors in the code.

In Kotlin we can create additional threads as well. But, we can handle them with a better approach called Coroutines. Coroutines use less memory compared to threads. Coroutines can perform long-running and intensive tasks.

Null Safety

A billion-dollar mistake in Java, that is it does not provide Null safety. Because of that NullPointerExceptions occur. In Java, you can assign a null value to any type of variable. And when a developer uses an object reference that has a null value then NullPointerException comes.

In Kotlin if a developer gives Null as a value. It will generate a compiler error. In Kotlin all the types are by default non-nullable. To assign a null value to a variable in Kotlin we need to mark the variable as nullable. This needs a ‘ ? ‘ after the type of that variable. Like this:

val age: Int? = null

This leads to no NullPointerException.

Constructors Support

Kotlin constructor use is simple and basic. In Kotlin a class can have one or more than one secondary constructors. Along with the primary constructor. Just In the class declaration, we have to add these secondary constructors.

Smart Casts

Kotlin has a feature called smart casts. Smart casts automatically handle the redundant casts.


Kotlin vs java Which One Is Better
Kotlin vs java Which One Is Better



We have discussed some basic features on how Kotlin can be better than Java. But in Java, we too have a few things that Kotlin doesn’t support such as Static Members, Non-private Fields, Ternary Operator, etc. Well besides these similarities and dissimilarities both languages are completely interoperable. We can convert a java code to Kotlin and Vice Versa. We can also convert Kotlin code to JavaScript or to native code.

Kotlin vs Java which one is better this question is still debatable. A huge number of developers are still using Java for Android development. But for a sure number of Kotlin developers is increasing day by day.

If we talk about Kotlin vs Java syntax then it doesn’t make a big difference. In my opinion, Java programmers can easily migrate to Kotlin without any difficulty.

In my opinion, Kotlin is better than Java because it has some great features that Java doesn’t provide. Such as Null Safety and Code conciseness. Another advantage is that Kotlin was designed to fulfill those requirements that previously developed languages like Java didn’t have. But both languages have their advantage over the other.


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