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Java Vs Kotlin

Java and Kotlin both are object-oriented programming languages. But both are used for different purposes. Kotlin is used to develop android applications while Java is mainly used for developing enterprise applications. In this section, we have discussed the differences between Java and Kotlin.

Java Vs Kotlin


Java is the most popular, widely used, object-oriented programming language designed by James Gosling. Using Java, we can create a variety of applications such as desktop applications, enterprise applications, cloud-based, and web-based applications. Usually, it is used to develop the back-end. Java is the primary choice for the developers when it comes to Android app development. Note that Android itself is written in Java.

Why Java?

Though no longer the only officially supported language for Android development and, of course, far from the only choice for web programming, Java keeps pace with the alternatives. And since that's not only thanks to its respectable age, let's explore what advantages Java has to offer. Another reason to use Java is that it is highly scalable, robust, and secure. This is the reason; it is used widely.

  • Easy to learn.
  • It is a powerful development tool.
  • Available free of cost.


  • Memory is managed by the JVM automatically.
  • It is more secure.
  • Platform independent.
  • Highly secure
  • Provides vast community support.


  • Syntaxes in Java are complex and large.
  • Verbose and complex code.
  • Its performance is poor.

Example of Java Code


Hello, World!


Kotlin is also an object-oriented programming language just like Java developed by JetBrains. It is a general-purpose, open-source, sterically-typed, cross-platform pragmatic programming language with type inference. It is particularly designed to interoperate with Java and also to improve the existing Java models by offering solutions to API design deficiencies.

Kotlin is specially designed for JVM and Android. A combination of JVM and android combines object-oriented and functional programming features. Note that Kotlin's standard library totally depends on the Java class library. It focused on safety, clarity, and interoperability.

The combination of Kotlin and Java reduces the boilerplate code which is good for android developers. Kotlin source code is compiled by the LLMV (compiler technology). It compiles Kotlin source code into the stand-alone binaries.

Most of the companies like Twitter, Pinterest, Netflix, Uber, etc. switching to Kotlin for android app development. Because it is lightweight, clean, concise, and less verbose especially for writing callbacks, data classes, and getter/setters.

Google LLC considers it as the second official language for app development. It is the most popular programming language among android developers.

Why Kotlin?

Kotlin is a modern, concise, interoperable, and safe programming language. It provides a productive way to write a server-side application. It is compatible with the Java ecosystem because we can use our favorite framework and libraries with it. It also saves time and effort.

  • It supporting new JVM features, like string concatenation via invokedynamic.
  • Improved performance and exception handling for KMM projects.
  • Experimental extensions for JDK path Path("dir") / "file.txt".


  • It is compatible with existing Java code.
  • It is interoperable with Java.
  • It increases team productivity.
  • It is easily maintainable.
  • It is less buggy and more reliable.
  • Provides rich API for application development.


  • The compilation speed of Kotlin is slow.
  • It has a small developer community.
  • Memory consumption is high.

Example of Kotlin Code



Hello, World!

Difference Between Java and Kotlin

In the following table, we have made head to head comparison between Java and Kotlin. Let's see which programming language won the fight.

Features Java Kotlin
Primitive Type Primitive types in Java are not objects. Primitive types are objects.
Product It is a product of Oracle Corporation. It is a product of JetBrains.
Used For It is used to develop stand-alone applications and enterprise applications. It is used to develop server-side applications and android application development.
Compilation Time Java's compilation time is pretty fast. Its compilation time is slow in comparison to Java.
File Extensions Java uses the extensions: .java (for source file), .class (for class file), .jar (for archived file). Kotlin uses the extensions: .kt (for Kotlin source file), .kts (for Kotlin script file), .ktm (for Kotlin module)
Checked Exceptions In Java, we take care of the checked exception by using the try-catch block. There is no need to catch or declare any exception.
Concise The code is not concise in comparison to Kotlin. It reduces the boilerplate code.
Extension Function We need to create a new class and inherit the parent class if we want to extend the functionality of an existing class. So, the extension function is not supported by Java. We can extend a class with new functionality by using the extension function.
Widening Conversion Java supports the implicit conversion so we can convert a smaller type to a bigger one. Kotlin does not support the implicit conversion. So, we cannot convert the smaller type to a bigger one.
Code Comparison The line of code is just doubled than Kotlin. It reduces the line of code to half.
Community Support Java provides a very large community. Its community is not so huge as Java.
Casting In Java, we need to identify and perform the casting. Kotlin supports the smart cast, which means that it identifies the immutable type and performs implicit casting automatically.
Type interface It is mandatory to specify the data type, explicitly. It is not mandatory to specify the type of variable, explicitly.
Null Values We can assign null values to variables but cannot assign null values to an object. We cannot assign null values to any variable and objects.
Ternary Operator It is available in Java. It does not support ternary operator.
Coroutines Support Multithreading feature of Java makes it more complex because managing the multiple threads is a difficult task. Java blocks the thread if we initiate a long-running intensive operation like network I/O or CPU operations. Like Java, we can create multiple threads (long-running intensive operations) in Kotlin also but coroutine can suspend a thread execution at a certain point without blocking the other threads.
Functional Programming Java is not functional programming. It is a combination of functional and procedural programming language.
Data Classes If we need a class that can hold data only, for this we need to define getter, and setter methods, constructors, and other functions. If we want to do the same in Kotlin, we declare the class with the keyword Data. Rest the work such as creating constructor, getter, and setter methods for the fields are done by the compiler.

Finally, we can opt for Kotlin if we want to develop an android application or want to do server-side programming. We should go with Java if we want to develop an enterprise application or desktop application or web application.

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