JAVA vs Kotlin: Differences you must know

Authored By: Ankita Prajapati

JAVA is a widely used object-oriented programming language and software platform that runs on billions of devices. Before Kotlin, JAVA was the official and preferred language for Android Development.

Programming in Kotlin is simple, safe, interoperable, and modern. It offers a useful technique for creating server-side applications. Due to the fact that we can utilize our preferred frameworks and libraries with Kotlin, it is compatible with the Java environment.

Read the differences between JAVA and Kotlin.

Who developed them?

Java has been developed by Oracle Corporation while Kotlin has been created by JetBrains.

What are they used for?

JAVA is majorly used for creating standalone applications and business applications, whereas Kotlin mainly focuses on server-side application development and android application development.

Difference between Compilation Time

Java’s compilation process is fairly quick while Kotlin takes longer to compile. 

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File Exceptions:  

The file extensions used by Java (for source files),.class (for class files), and.jar (for archived files).

The file extensions used by Kotlin are. kt (for Kotlin source files), .kts (for Kotlin script files), and. Kt (for Kotlin module)

Whose code has the quality of Conciseness?

Code written in Java is a bit long while Kotlin offers a lot of conciseness and makes it easy to use.

Extension Functionality 

To increase the functionality of an existing class in JAVA, we must build a new class and inherit its present class. Therefore, JAVA does not support extension functionality.

Kotlin, on the other hand, uses the extension function to add new functionality to a class. 

Widening Conversion

Java allows implicit conversion, allowing us to increase the size of a smaller type. 

The implicit conversion is not supported in Kotlin. Therefore, we are unable to change the smaller type to a larger one. 

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Null Values

In JAVA, variables can have null values assigned to them, but we cannot do the same for objects. 

While in Kotlin, null values cannot be assigned to any variables or objects.

Ternary Operators

With JAVA, we can use ternary operators but Kotlin does not support it.

Coroutines Support 

Java’s multithreading feature adds to its complexity. If we start a time-consuming, lengthy task like network I/O or CPU operations, Java blocks the thread.

Similar to Java, Kotlin allows for the creation of many threads (long-running, intensive tasks), but coroutines allow for the suspension of a thread’s execution at a certain time without blocking other threads. 

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Functional Programming 

Programming in Java is not functional whereas Kotlin combines procedural and functional programming languages. 

Data Classes 

In JAVA, we must define getter, setter, function Object () {[native code]}, and other functions if we need a class that can only hold data. 

In Kotlin, we declare the class using the keyword Data if we wish to accomplish the same thing. The compiler handles the remainder of the job, such as constructing function Object () {[native code]}, getter, and setter methods for the fields. 

Example of a JAVA Code

					class YourEngineerExample   


public static void main(String [] args)    


System.out.println("Your, Engineer!");    



Output: Your, Engineer!

Example of a Kotlin Code


fun main(args : Array<String>)    


println("Your, Engineer!")   


Output: Your, Engineer!

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