Java vs. Kotlin: The Key Differences Explained

When comparing the capabilities and approaches of two programming languages, Java and Kotlin seem to be fairly comparable.

Being object-oriented and cross-platform, both Java and Kotlin are open-source. Both have the same syntax and may be executed on any system that has a Java Virtual Machine (JVM). The fact that one can transfer Kotlin code into Java and vice versa shows how compatible they are. But this is where we start to see certain differences while comparisons start.

Read on to get the lowdown on Java and Kotlin, how they're similar and different, and how to use them effectively.

What Is Java?

Sun Microsystems' James Gosling, Mike Sheridan, and Patrick Naughton created the Java programming language. It came out in May of 1995. Websites, desktops, computers, laptops, mobile devices, IoT devices, and countless more have relied on Java programs for over three decades. As the foundation of the Android Software Development Kit (SDK), the Java programming language is an integral part of Android.

Java is an Object-Oriented, free, and open-source computer language that can run on many platforms. Being one of the first languages to enable developers to "write once, run anywhere" (Java)—a capability made possible by the Java compiler—it was groundbreaking. A system's hardware processor may access the Bytecode that the compiler produces; the JRE interprets the Bytecode and translates it to binary machine code. This is the reason for Java's versatility.

What Are The Benefits And Drawbacks Of Java?

Among computer languages, Java ranks high in popularity, and rightfully so. Learning and using it is a breeze. You can read a mountain of paperwork, both official and community-backed, spanning decades. On top of that, it's dependable and steady. Although Java has many advantages, it also has certain disadvantages. This is why languages like Kotlin have emerged as alternatives to Java.

Benefits Of Java

Adopts a Multithreaded Approach

Application performance and reaction times to user interface events are both enhanced by multithreading in Java. It improves resource usage, which might lead to more device compatibility, which is particularly helpful for older, sluggish devices that have less processing power.

Thorough Documentation

Since Java has been around for 30 years, programmers have access to a wealth of documentation, both official and community-driven. They may now speed up the software development life cycle (SDLC) by easily troubleshooting difficulties. Additionally, Oracle continues to provide support for Java, with the most recent version being Java 21, which was published in September 2023.

Object-Oriented Programming

As an OOP language, Java allows developers to build data and method-containing objects. The ability to construct flexible programs—applications with functionality cut down into different, individual pieces—and reuse code makes this strategy simpler to develop with and quicker than procedural languages.

Drawbacks Of Java

Inadequate Design of User Interfaces

The tools available for creating Graphical User Interfaces (GUIs) in Java are restricted. These technologies don't have what it takes to build sophisticated user interfaces (GUIs), which is what today's users want. Python and C# are two languages that offer more robust capabilities for creating user interfaces.

Decline in Popularity

Use of Java has been a gradual decrease throughout the years. At the moment, it ranks just below TypeScript, SQL, Python, HTML/CSS, and JavaScript as the world's seventh most used programming language. There may be a shift in programming away from Java and toward more modern languages like Kotlin as a result of this.

Challenging to Read and Comprehend

Java requires more code to perform similar functions as Kotlin since it is a more expressive language. Clients may end up spending more time and money due to the lengthened software development life cycle caused by this need.

What Is Kotlin?

Kotlin, created and published in July 2011 by JetBrains, is a computer language. This language is open-source, strongly typed, and designed for general-purpose applications. Using both object-oriented and functional programming capabilities, it can operate on both Android and JVMs. The year 2019 saw Google's announcement that Kotlin will be the language of choice for future Android apps.

The primary goal in developing Kotlin was to provide a more secure, organized, and efficient substitute for Java. Features like string concatenation, null safety, and coroutines were included by JetBrains to do this. For creating apps for Android, Kotlin is the go-to language.

What Are The Benefits And Drawbacks Of Kotlin?

Kotlin is a less developed programming language, although it is quicker and more precise than Java. The benefits and drawbacks of adopting Kotlin are explained here.

Benefits Of Kotlin

Swifter Than Java

Due to the reduced amount of code required to do the same tasks in Kotlin compared to Java, the language is easier to read and understand. Programmers may save time and money by removing unimportant code, which speeds up the software development life cycle (SDLC) and benefits the customer.

Null Safety

One of the leading reasons for applications to crash is null point problems. These errors happen when a program tries to access data that is located in an incorrect part of memory. To get around this, Kotlin has a feature that stops programmers from assigning null values, a feature known as null safety. Consequently, this facilitates code maintenance and repair for them.

Object-Oriented and Functional Programming

Applications written in Kotlin may take advantage of both object-oriented and functional programming techniques. Because of this, programmers have more options for tackling difficult issues and may move between different programming styles.

Drawbacks Of Kotlin

Immature Compared to Java

With a far younger user base and less extensive documentation, Kotlin isn't quite ready to take on Java just yet. As a result, programmers may spend more time troubleshooting, and novice programmers may find it more challenging to grasp Kotlin. Java developers also have access to a plethora of testing frameworks that guarantee their code is free of bugs and errors.

Keeps Java Proficiency Necessary

Kotlin is its programming language, however, it shares several syntactic similarities with Java. To fully utilize Kotlin, programmers should preferably have a basic understanding of Java.

Compilation Time Is Too Long

Kotlin compiles slower than Java, but it creates incremental builds quickly. Why? The reason is that Kotlin's foundational code base is still Java. As a result, compiling more data is required for Kotlin than for standalone Java, independent of the project scope or size.

Key Differences: Java Vs. Kotlin

The differences between Kotlin and Java are becoming more apparent. While they do have certain commonalities, such as being used to build online and mobile applications and sharing a common language and set of functionality, that is about where the similarities end. Java and Kotlin differ in several important ways, and we'll go over them all here.

1. Programming Styles

Due to its nature as an object-oriented language, Java does not provide support for many programming paradigms. As opposed to Java, the more flexible Kotlin language allows for both object-oriented and functional programming.

2. Performance

The performance of applications and user interface reaction times are both enhanced by the capability for multithreading in both Java and Kotlin. But with Kotlin's coroutine support, developers may more easily create programs that can conduct asynchronous operations. Also, coroutines prevent background processes on Android applications and other long-running activities from hogging the main thread and crashing the program.

3. Android Development

At this time, Android app developers prefer Kotlin over any other language. Its compatibility with Android Studio integrations is a major factor in this. Because of this, developers can use Kotlin with confidence, knowing that their Android apps will be compatible with a vast array of plugins.

4. Web Development

Spring, JSP, and JSF are just a few of the many frameworks that Java offers, making it an ideal choice for developing online applications. For this and other reasons, Java is still widely used by programmers for creating web apps. Another area where Java shines is in legacy projects, such as those dealing with long-running websites.

Future Trends: Java Vs. Kotlin

The future seems bright for both Java and Kotlin. A rising demand for simpler and more efficient code is indicated by Kotlin's contemporary features like null safety, smart casts, and coroutines. Java, on the flip side, is still a go-to for complicated, large-scale applications because of its stability and library support. To keep up with the demands of developers and the computer sector as a whole, both languages will likely undergo constant evolution and include new features.

Future Trends In Kotlin

The usage of Kotlin has been on an encouraging rising trend over the last many years. Its interoperability with Java, current features, and robustness are the reasons behind this. The short syntax and compatibility with Java of Kotlin have led to a dramatic rise in the language's popularity, particularly in the Android app development space. Because of its many useful features, more and more developers are likely to switch to Kotlin, which bodes well for the language's future.

Future Trends In Java

Java's user base has remained consistent due to the language's longevity. Java has a strong ecosystem and many uses, thus, it remains relevant even if it is seen as older than languages like Kotlin. Back-end development and corporate systems continue to use it heavily. In regions where Kotlin and other new languages have begun to make inroads, however, the pattern indicates that Java's popularity is slowly but steadily declining.

Which One Is Better?: Java Vs. Kotlin

It might be difficult to decide between Java and Kotlin while developing software, especially for mobile applications. There are advantages and disadvantages to both languages. A massive community of developers supports the open-source language Java, which has endured for a long period. Conversely, Kotlin is quickly becoming a popular alternative to Java since it can create native code for several platforms and is compatible with current Java code.

Handling long activities and creating several background threads are important issues in mobile development. Thanks to its backing of coroutines, which makes the process much easier, Kotlin is great in this regard. Reduced reliance on explicit casting checks is another benefit of using Kotlin's type inference and smart-cast features. One way to make the switch easier is to leverage Java code written in Kotlin.

You aren't limited to a black-and-white decision when deciding between Kotlin and Java. It is possible to combine the two languages and make the most of their respective abilities. In the end, it's up to you to decide based on your project needs, level of language proficiency, and openness to new ideas. Do yourself a favor and learn all you can about Kotlin and Java so you can choose the one that's right for you.