Kotlin vs Java – Difference Between Them

Kotlin VS Java – Overview

Kotlin combines features of both object-oriented and functional programming, whereas Java is limited to object-oriented programming.
Kotlin allows users to create an extension function, while Java doesn’t offer any extension functions.
Kotlin doesn’t offer implicit conversions, and Java supports implicit conversions.
There are no null variables or objects in Kotlin; on the other hand, Null variables or objects are part of the Java language.
Kotlin doesn’t support static members, while Java uses static members.
In Kotlin, variables of a primitive type are objects, while in Java, Variables of a primitive type aren’t objects
Kotlin supports Lambda Expression, whereas Java doesn’t support Lambda expression. (Lambda expressions are added in Java 8)
Kotlin doesn’t require any variable datatype specifications, while Java requires variable datatype specifications.
Kotlin doesn’t require any variable datatype specifications, but Java requires variable datatype specifications.
Kotlin programs don’t require semicolons in their program, while Java programs do need a semicolon.
Language scripting capabilities allow you to use Kotlin directly in your Gradle build scripts, while Java does not offer language scripting capabilities.

Here, I have analyzed the differences between Kotlin and Java and will comprehensively evaluate their pros and cons.

What is Kotlin?

Kotlin is an open-source programming language that can run on Java Virtual Machine (JVM). The language can run on numerous platforms.

It is a language that combines Object Oriented Programming (OOPs) and functional programming in an unrestricted, self-sufficient, and distinctive platform.

History of Kotlin

Here are the pivotal landmarks from the history of Kotlin that I’ve witnessed:

In 2016, Kotlin v1.0 was launched
In 2017, Announcement of Google on the first-class support of Kotlin in Android
In 2018, Kotlin v1.3 version was released, bringing coroutines for asynchronous programming.
In 2019, Google announced Kotlin as its preferred programming language for Android application developers

Features of Kotlin

Here, let me share the important features of Kotlin as we have applied them to our projects.

Offers Trimmed Coding
Kotlin utilizes JVM, which combines the features of OOPs and functional-oriented programming.
Offers fast compilation
Kotlin can support a variety of extension functions without making any changes to the code
You can write Kotlin code using IDE or using the command-line interface
Smart feature casting helps you to cut down the application costs and improves its speed or performance.

Example of Kotlin Code

fun main(args : Array<string>)   
{  
println("Hello, World!")  
}

Output:

Hello, World!

Advantage of Kotlin

In our experience, here are the benefits and pros of Kotlin:

Using the Kotlin Multi-platform framework, you can extract one common codebase that will target all of them at the same time
Kotlin offers built-in null safety support, which is a lifesaver, especially on Android, which is full of old Java-style APIs.
It’s more concise and expressive than Java, which means there is less room for error.
Offers user-friendly and understandable coding norms
Divides large apps into smaller layers.
Uses lots of function types and specialized language structures like lambda expressions.
Helps developers to create extension functions
Offers a very simple and almost automated way of creating data classes
Kotlin is a statically typed language, so it is very easy to read and write.
This language allows the exchange and use of information from Java in various ways.
It’ll take less time to write new code in Kotlin.
It’s quite easier to deploy Kotlin code and to maintain it at scale.

Disadvantage of Kotlin

Here, I will outline the cons and drawbacks of using Kotlin:

Small community of developers, so it lacks learning materials and professional assistance.
Java doesn’t offer a function of checked exceptions that may lead to errors.
Slower compilation speed than Java
Kotlin, being a highly declarative language, sometimes helps you to generate great amounts of boilerplate in corresponding JVM bytecode

What is Java?

Java is a multi-platform, object-oriented, and network-centric programming language. It is among the most used programming languages. It is also used as a computing platform, and it was first released by Sun Microsystem in 1995. It was later acquired by Oracle Corporation.

History of JAVA

Here, we’ll look at important landmarks from the history of the Java language that we have witnessed and analyzed.

The Java language was initially called OAK. Originally, it was developed for handling portable devices and set-top boxes. Oak was a massive failure.
In 1995, Sun changed the name to “Java” and modified the language to take advantage of the burgeoning www (World Wide Web) development business.
Later in 2009, Oracle Corporation acquired Sun Microsystems and took ownership of three key Sun software assets: Java, MySQL, and Solaris.

Features of Java

Here are the important features of Java that we’ve come to appreciate:

Write code once and run it on almost any computing platform
It is designed for building object-oriented applications.
It is a multi-threaded language that allows automatic memory management.
Facilitates distributed computing as its network-centric.

Example of Java Code

 class A {
 public static void main(String args[]){
     System.out.println("Hello World");
 }
}

Output:

Hello World

Advantages of Java

In my experience, here are the benefits of Java:

Checked exceptions that improve error detecting and solving
Detailed documentation is available.
A large pool of skilled developers available
A huge array of 3rd party libraries
It allows you to form standard programs and reusable code.
It is a multi-threaded environment that allows you to perform many tasks simultaneously in a program.
Excellent performance
Easy to navigate libraries

Disadvantages of Java

In my experience, here are the cons and disadvantages of Java:

Not very suitable for Android API design because of a number of limitations
Demands a lot of manual work, which increases the number of potential errors
JIT compiler makes the program comparatively slow.
Java has high memory and processing requirements.
It does not provide support for low-level programming constructs like pointers.
You don’t have any control over garbage collection as Java does not offer functions like delete() or free().

Difference Between Kotlin and Java

In our analysis, we will delineate the differences between Kotlin and Java that I have come to understand.

Kotlin	Java
Kotlin allows users to create an extension function.	Java doesn’t offer any extension functions.
Kotlin doesn’t require too much work for data classes.	Java developers write and construct a lot of elements to develop classes
Kotlin doesn’t offer implicit conversions.	Java supports implicit conversions.
There are no null variables or objects in Kotlin.	Null variables or objects are part of Java language.
Kotlin combines features of both object-oriented and functional programming.	Java is limited to object-oriented programming.
Kotlin doesn’t support static members.	Java uses static members.
Variables of a primitive type are objects	Variables of a primitive type aren’t objects
In Kotlin, we can have one or more secondary constructors.	In Java, we can’t have secondary constructors. However, it can have multiple constructors.
Kotlin string template also supports expression.	Java string doesn’t support expression like Kotlin.
It’s quite easier to deploy Kotlin code.	It is hard to deploy Java code.
Kotlin programs don’t require semicolons in their program.	Java program does need a semicolon.
In Kotlin, coroutines are concurrency design patterns that can be used to simplify code.	Java uses two coroutine options: 1) Rx Java and 2) Project loom.
Kotlin doesn’t have any wildcard-types.	Wide-card is available in Java.
Kotlin’s type of system has inbuilt null safety.	NullPonter Exception is mainly responsible for the development of Java and Android.
Smart cast feature is available in Kotlin.	Smart cast feature is not available in Java.
Kotlin doesn’t require any variable datatype specifications	Java requires variable datatype specifications.
Kotlin supports Lambda Expression.	Lambda expressions are added in Java 8
Lazy-Loading feature is available in Kotlin.	This feature is not available in Java.
Language scripting capabilities allow you to use Kotlin directly in your Gradle build scripts	Java does not offer language scripting capabilities.
It supports modern programming concepts like delegates, extensions, and higher-order functions.	Java supports the OOPS programming concept.
The average salary for a Java developer is $104,793 per year.	The average salary for “Kotlin” ranges from approximately $107,275 per year for Software Engineers to $121,034 per year for Android Developers.

How to Choose Between Kotlin and Java

When I consider all the pitfalls of Java, especially the problem with NullPointerExceptions, Kotlin seems to be the better one among the two.
Although Java is still an essential language for every android app development as the Android OS itself is based on the same.
If you are looking to future-proof your Android app development services, then you should hire Kotlin developers for the same.