With the rise of technology and mobile applications, developers are looking for new technologies to help them create innovative and valuable products. Two languages that have been gaining popularity among developers are Java and Kotlin. Both Java and Kotlin offer their own unique features and advantages. So, what’s the difference between Java vs Kotlin?

Android applications are an excellent choice for growing your business but which language is best for creating the app is the real trouble.

This blog post will explore Java vs Kotlin so you can determine which one is best suited for your project. We’ll look at how both languages can be used in Android development and what features they offer so developers can decide which one to choose. 

Let’s start with the basic definitions.

What is Java?

Java is a multi-purpose and powerful programming language that enables developers to create robust, highly functional applications. Java is an object-oriented language with a wide range of features, including exception handling, garbage collection, and multithreading. Java supports static members, implying that only one such instance is created and shared across all class cases.

Java supports widening conversions implicitly. Therefore, it allows the conversion of smaller-sized data types to larger ones.

What is Kotlin?

Kotlin is a statically typed, general-purpose, open-source, community-driven language. JetBrains, the company behind IntelliJ IDEA, PyCharm, WebStorm, and other popular IDEs, created Kotlin. Kotlin is free and open source under the Apache 2.0 license.

Kotlin is a concise, safe, interoperable and tool-friendly language that can be used to build applications in various domains such as mobile, web, server-side, embedded systems etc.

Kotlin runs on JVM and can be used to develop Android apps. Kotlin also has first-class support on primary build tools like Gradle and Maven. In addition, Kotlin works well with all existing Java libraries and frameworks, and thus there’s no need to learn any new frameworks when using Kotlin.

Kotlin aims to be a more expressive and concise alternative to Java with features like null safety, type inference, higher-order functions etc.

In Kotlin, you can write your own extensions to the standard library. You can also create plugins that extend the functionality of the standard library. Kotlin is an open-source project that will continue to develop over time.

Why are we comparing Kotlin vs Java?

Java vs Kotlin is two of the most popular programming languages in the world. While Java has been around for over 20 years, Kotlin was only released in 2016. Despite being a newer language, Kotlin has already gained much popularity, especially among Android developers.

One of the main reasons why Kotlin is gaining popularity is because it addresses some of the pain points that Java developers have been dealing with for years. For example, Kotlin has null safety built into the language, eliminating a whole class of potential errors in Java code.

Another significant advantage of Kotlin over Java is that it is fully interoperable with Java. This means you can use Kotlin libraries in your Java projects and vice versa. This makes it very easy to gradually migrate existing Java codebases to Kotlin without completing a rewrite.

So why are we comparing Kotlin vs Java? 

Simply put, Kotlin is a great alternative to Java for modern development projects. If you’re starting a new project from scratch or looking to migrate an existing Java codebase to a more modern language, then Kotlin is definitely worth considering.

Comparing the Features and Functionalities of Kotlin and Java

Comparing the Features and Functionalities of Kotlin and Java

Kotlin and Java are two of the most popular programming languages in the world. Kotlin is a statically typed programming language. It has many similarities with Java but is also different in many ways. Both have their own pros and cons, but which one is right for your project? Here’s a look at Java vs Kotlin:


I. Syntax and basic structure for Java

  • Java syntax is heavily influenced by C and C++ and uses a similar structure of classes and objects.
  • it is used a curly brace syntax for defining classes, methods, and control structures.
  • Java also uses the “public static void main” method as the entry point for executing a program.
  • Java requires the use of explicit data types for variables and method parameters.
  • Java does not have built-in support for functional programming constructs like lambdas and closures.

II. Syntax and basic structure for Kotlin

  • Kotlin’s syntax is more concise than Java, with fewer boilerplate codes and more expressive type inference.
  • Kotlin uses a similar class and object structure but it also supports other types of declarations such as data classes and sealed classes.
  • Kotlin also uses the “main” function as the entry point for executing a program, but unlike Java, the “main” function is not required to be marked as “public” or “static”
  • Kotlin’s type inference allows for type declarations to be omitted in certain situations, making the code more readable.
  • Kotlin has built-in support for functional programming constructs such as lambdas and higher-order functions, which allows for more expressive and concise code.

Kotlin is a language that compiles to JVM bytecode, like Java. It’s also statically typed and has a concise syntax, similar to Python or JavaScript.

Type Interference

Kotlin supports type inference (the ability to infer the types of variables based on their context), which can make your code more concise if you use it correctly.

Variables and Constants in Kotlin and Java

One of the biggest differences between Kotlin and Java is in their syntax for declaring variables. While both languages use a variable, Java uses a type declaration to specify what type of object the variable will hold, while Kotlin doesn’t do this at all. Instead, it would help if you used an explicit type annotation: var name: String = “John”;

In Kotlin, this can be shortened down to just name: String = “John” (without having to declare which class your variable should belong to). Overall, this makes for a much more concise codebase because we don’t need all those extra brackets around each declaration when we could just say, “here’s my string” instead.

Null Safety

In Java, null values can be allocated to the objects. So, when a member of a null reference is obtained, its outcome will be a NullPointerException. 

On the other hand, we can set null values by default in Kotlin, but it has better code stability by practicing null safety.

Smart Casting

The developer must check the variable type in Java and launch it according to per operation. Whereas in Kotlin, intelligent casting features are automatically managed by the compiler.

Platform Compatibility

Java compiles to bytecode for JVM and JavaScript using Nashorn and Rhino JS Engines. However, Kotlin supports both bytecode and JavaScript and native code compilation.

Java vs Kotlin Use Cases

When to use Java?

  • When working on a large, complex enterprise project that requires a lot of legacy code.
  • When working with a team of developers who are primarily experienced with Java.
  • When interoperability with other Java libraries and frameworks is a requirement.
  • When large computational tasks are required, Java’s JVM provides good performance and memory management.

When to use Kotlin?

  • When developing new applications and features that can take advantage of the conciseness and expressiveness of the language.
  • When working on a small or medium-sized project where the additional capabilities of Kotlin such as null safety, type inference, and functional programming constructs can be beneficial.
  • When developing for Android, Kotlin has first-class support and fully inter-operable with Java.
  • When working on a project that has stringent requirements for maintainability, readability, and code safety.

These are just some of the key differences between Kotlin vs Java. Understanding these differences is important because they can help you choose which programming language will best suit your needs at work or even at home when building apps for Android devices.

Key Takeaway:

Here’s a quick overview of Kotlin vs Java:

  • Kotlin is a statically typed programming language, while Java is a dynamically typed language.
  • Java is a legacy language, while Kotlin is a newcomer.
  • Java has checked exceptions, while Kotlin does not have checked exceptions.
  • Kotlin code is much more concise than Java code.
  • Kotlin has built-in null safety, while Java does not. This makes Kotlin much safer than Java.
  • Kotlin supports higher-order functions, while Java does not. This makes Kotlin much more flexible and powerful than Java.

Kotlin vs Java: which is better?

No matter what language you learn first, you’ll have a tough time learning a second. It’s just the way our brains work. So, if you want to know whether Kotlin or Java is better, it really depends on which one you want to learn first. If you come from a background in Java, then Kotlin will probably be a better choice for you. However, if you’re new to programming, Java might be the better option to start with.

Some key differences between Kotlin and Java make Kotlin a more attractive option for some developers. For starters, Kotlin is a statically typed language, which means that variables can only hold values of certain types. This can help prevent errors in your code and make your code more readable.

Another key difference is that Kotlin doesn’t have checked exceptions like Java. This means that you don’t have to catch or declare any peculiarities in your code, which can save you time and hassle. Finally, Kotlin provides null safety, which means that it can help prevent NullPointerException errors in your code.

The table below compares Java and Kotlin head to head. Let’s see which programming language comes out on top.

Null SafetyJava has null pointers, which can lead to null reference exceptions.Kotlin has null safety built-in, reducing the likelihood of null reference errors.
Extension FunctionsJava does not support extension functions.Kotlin supports extension functions, allowing for a more concise codebase.
Lambda ExpressionsJava supports lambda expressions, but they can be verbose and hard to read.Kotlin’s lambda expressions are more concise and easy to read.
Type InferenceJava has limited type inference capabilities.Kotlin has improved type inference capabilities, leading to a more concise codebase.
Data classesJava does not have built-in support for data classes.Kotlin has built-in support for data classes, allowing for a more concise codebase.
CoroutinesJava does not have built-in support for coroutines.Kotlin has built-in support for coroutines, allowing for more efficient concurrency.
Smart CastsJava does not have built-in support for smart casts.Kotlin has built-in support for smart casts, allowing for a more concise codebase.
Operator OverloadingJava does not support operator overloading.Kotlin supports operator overloading, leading to a more readable and concise codebase
Java Vs Kotlin

So, which one is better in Java vs Kotlin? Ultimately, it depends on your individual needs and preferences as a developer.

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About Ritika

Ritika is an avid content curator who loves chatting about all things Industry and Technology. She writes about Web App Development, Designing, Marketing, even Machine Learning, and AI.