Kotlin vs Java: Which is the best choice for your next project in 2024

Considering Kotlin vs. Java for your next project? Discover the key differences, advantages, and use cases to make an informed decision for your software development needs.

Selecting the right programming language is a pivotal decision for the success of your project. In the realm of Android development, and now more broadly across various development landscapes, Kotlin and Java emerge as two leading contenders. Each language brings its unique set of advantages and challenges, sparking lively discussions among developers about which one to choose.

This choice is not just about technical capabilities but also about aligning with project goals, team skills, and future maintainability. Understanding the strengths and limitations of Kotlin and Java can help guide this important decision, ensuring your project is built on a solid and suitable technological foundation.

Popularity – Java vs. Kotlin

As of 2023, both Kotlin and Java remain highly popular among developers, especially for Android app development and enterprise applications. The precise usage statistics can vary across different surveys and reports, but generally:

• Popularity of Java continues increase as it is one of the most widely used programming languages globally, ranked among the top in popularity on indexes such as the TIOBE Index and GitHub's Octoverse. Despite the growth of newer languages like Kotlin, Java maintains a strong presence in enterprise environments and among educational institutions.
• Popularity of Kotlin has steadily increased, especially among Android developers. Google's push for Kotlin on Android has significantly influenced its growth. JetBrains reported a substantial year-over-year increase in Kotlin users, with millions of developers now using Kotlin.

Usage Of Kotlin And Java in Software Development

• Mobile Development: Kotlin shows a higher percentage of adoption (85%) compared to Java (60%), reflecting its popularity for Android app development following Google's endorsement.
• Enterprise Applications: Java leads with a 90% adoption rate, highlighting its stronghold in enterprise environments due to its robustness and extensive libraries.
• Web Development: Both languages are used significantly, with Kotlin at 60% and Java at 70%, showing Java's continued relevance and Kotlin's growing adoption in web applications.
• Educational Projects: Java has a higher usage (75%) compared to Kotlin (25%), indicating Java's widespread adoption in academic settings and educational institutions.
• Startup Projects: Kotlin is preferred more (70%) than Java (50%) in startup projects, likely due to its modern features and concise syntax that can accelerate development time.

This graph represents a hypothetical scenario to demonstrate why businesses might choose Kotlin or Java based on their project requirements and each language's advantages in different sectors. ​

Comparison of Kotlin and Java:

Java has been a mainstay of Android development since its inception, offering robustness, portability, and an extensive ecosystem. Kotlin, on the other hand, is a newer language that has gained popularity for its modern features, conciseness, and interoperability with Java. Google's endorsement of Kotlin as a first-class language for Android development in 2017 has further boosted its adoption.

Comparing Java and Kotlin involves examining various aspects such as features, advantages, disadvantages, applications, industries, and geographical usage. Both languages run on the Java Virtual Machine (JVM) and are widely used for Android development, among other applications. However, they have distinct characteristics that make them suitable for different use cases.

1. Features of Java vs. Kotlin

Features of Java:

• Mature and widely used programming language with a vast ecosystem.
• Object-oriented programming (OOP) language that enables the creation of modular programs and reusable code.
• Strongly typed language, requiring explicit declaration of variable types.
• Exception handling is more verbose compared to Kotlin.
• Requires more boilerplate code for certain tasks, like data classes.

Features of Kotlin:

Modern programming language that combines functional and object-oriented programming features.

• Offers more concise syntax compared to Java, reducing the amount of boilerplate code.
• Supports null safety through its type system to prevent the common null pointer exceptions.
• Extension functions allow adding new functions to existing classes without inheritance.
• Coroutines support for asynchronous programming, simplifying the management of long-running tasks and network calls.

Advantages of Java vs. Kotlin

2. Advantages of Java:

• Extensive libraries and frameworks, making it suitable for a wide range of applications, from web to Android development.
• Vast community support and resources available for learning and troubleshooting.
• High performance, especially in large-scale enterprise applications.

Advantages of Kotlin:

• Interoperable with Java, allowing the use of existing Java libraries and frameworks while gradually adopting Kotlin for new components.
• Less prone to errors due to null safety and concise syntax, leading to fewer runtime errors and crashes.

More expressive and reduces code verbosity, which can lead to faster development and maintenance.

3. Disadvantages of Java vs. Kotlin

Disadvantages of Java:

• More verbose, requiring more lines of code for tasks that could be accomplished more succinctly in Kotlin.
• Does not have built-in support for modern programming features like lambda expressions until Java 8, and still lacks features found in Kotlin.

Disadvantages of Kotlin:

• Smaller developer community compared to Java, which might lead to fewer resources and examples for specific use cases.
• Some argue it has a steeper learning curve for developers not familiar with modern programming concepts.

4. Top Apps Built with Java vs. Kotlin

Top Apps built with Java:

• LinkedIn
• Uber
• eBay

Top Apps built with Kotlin:

• Pinterest
• Trello
• Coursera

5. Top Industries that Use Java vs. Kotlin

Top industries that Use Java:

• Banking and financial services for server-side applications.
• Big Data, with technologies like Hadoop and Spark.
• Android app development, though Kotlin is increasingly popular here.

Top industries that use Kotlin:

• Mobile app development, especially for Android.
• Web development, through frameworks like Ktor.
• Enterprise backend development, complementing or replacing Java in some companies.

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6. Top Countries that Use Java vs. Kotlin

Both Java and Kotlin are used worldwide, but their adoption can vary based on regional industry focuses and technological ecosystems. For instance:

• Top Countries that use Java: Widely used in the United States, India, and European countries, especially in industries like finance, healthcare, and technology.
• Top Countries that use Kotlin: Rapidly gaining popularity in the same regions as Java, particularly among Android developers in North America, Europe, and Asia.

7. Language Features and Syntax

Kotlin: Modern and Concise

Kotlin is designed to be an improved version of Java, with a more concise syntax that reduces boilerplate code. It incorporates modern concepts such as null safety, extension functions, and coroutines for asynchronous programming. These features make Kotlin code more readable and easier to write and maintain.

• Null Safety: Kotlin's type system is designed to eliminate the dread of null pointer exceptions, a common source of runtime errors in Java applications.
• Extension Functions: Kotlin allows developers to extend existing classes with new functionality, a feature that promotes cleaner, more intuitive code without modifying the class's source code.
• Coroutines: Support for coroutines facilitates asynchronous programming, making it more straightforward to manage background tasks without complicating the codebase.

Java: Time-tested and Robust

Java's primary strength lies in its stability and predictability. Its syntax is more verbose than Kotlin's, which can lead to more boilerplate code but also makes it extensively clear. Java has been around for decades, providing ample time to refine its features and libraries.

Performance: Historically, Java has had a slight edge in performance and speed due to its more extended optimization period. However, Kotlin's performance is nearly on par, especially on the Android platform.

Memory Management: Java's garbage collection mechanism is highly optimized for large-scale applications, though Kotlin also performs efficiently.

8. Development Efficiency and Compilation Time

Kotlin: Streamlined Development

Kotlin's concise syntax and modern features lead to fewer lines of code, directly translating to faster development times. Integrating Kotlin into existing Java projects is seamless, allowing teams to gradually migrate to Kotlin without disrupting the development process.

However, Kotlin's compilation time can be slightly longer than Java's, particularly in incremental builds, though improvements in the Kotlin compiler are continuously narrowing this gap.

Java: Predictable Compilation

Java's compilation time is generally faster for clean builds, making it slightly more efficient in early development. However, Java's verbosity can slow the development speed over time as more code and complexity are added to the project.

9. Community Support and Ecosystem

Kotlin: Growing Ecosystem

Since its introduction, Kotlin has seen a rapidly growing community. The support from Google and the adoption by major companies have enriched Kotlin's ecosystem with libraries, frameworks, and tools designed explicitly for Kotlin or adapted from Java.

Documentation and Resources: Kotlin's official documentation is thorough and continuously updated. The community contributes with many learning materials, tutorials, and forums.

Java: Vast and Established

Java's ecosystem is vast, with many libraries, frameworks, and tools developed over its long history. This extensive support makes finding solutions to problems and hiring experienced developers easier.

Community Size: Java's community is one of the largest in the programming world, offering unparalleled resources and support.

10. Platform Compatibility

Kotlin: Multiplatform Capabilities

Beyond Android, Kotlin is designed to be a multiplatform language, allowing developers to share code between platforms like iOS, web, and desktop. Kotlin/Native compiles Kotlin code to native binaries, which can significantly streamline cross-platform development.

Java: Cross-platform with Limitations

Java's "write once, run anywhere" philosophy has been a cornerstone of its popularity. However, its cross-platform capabilities are more limited in mobile development, requiring tools like Java Micro Edition or frameworks that can add complexity to the development process.

Key Factors Businesses Should Consider While Choosing Between Java And Kotlin For Their Development Projects

Latest Versions - Java vs Kotlin:

The release of Java 21 in September 2023 marks a significant milestone in the Java ecosystem, introducing long-term support (LTS) that underscores its importance for future development projects. Among its key features, virtual threads stand out as a game-changer for developers, offering optimized handling of high-throughput concurrent applications, a boon for modern, scalable software. Pattern matching for switch statements further enhances the language's expressiveness and coding efficiency. Coupled with substantial performance and security updates, Java 21 solidifies its foundation and paves the way for innovative development practices. The extension of LTS for Java 11 through January 2032 ensures that this earlier version remains a viable and stable choice for developers, offering extended reliability for those maintaining legacy systems or those not yet ready to transition to the latest version.

Kotlin's journey continues with the release of Kotlin 1.9.20, showcasing significant advancements such as the Beta phase of the K2 compiler for all targets, which promises to enhance the language's compilation efficiency and stability. The announcement that Kotlin Multiplatform is now Stable heralds a new era for developers aiming to create seamless cross-platform experiences, reducing the need for duplicated code across various platforms. The new default hierarchy template simplifies the setup of multiplatform projects, streamlining the development process. Other noteworthy improvements include full support for the Gradle configuration cache in Kotlin Multiplatform projects, a custom memory allocator in Kotlin/Native enabled by default for optimized memory management, and performance enhancements to the garbage collector in Kotlin/Native. The expansion of Kotlin/Wasm with new and renamed targets and support for the WASI API in the standard library opens up new possibilities for Kotlin developers in web assembly environments, highlighting Kotlin's commitment to innovation and its adaptability to evolving technology trends.

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Conclusion: Kotlin or Java in 2024?

The decision between Kotlin and Java depends on several factors, including the project requirements, team expertise, and the specific use case. Kotlin is often the best choice for new Android projects due to its modern features, conciseness, and Google's support. It's especially suited for projects that require cross-platform development or aim to leverage modern programming paradigms.

With its robust performance, extensive ecosystem, and predictability, Java remains a solid choice for large-scale, enterprise-level applications or scenarios where the development team has a strong Java background and existing codebase.

In conclusion, both Kotlin and Java have their merits, making them viable options for your next project in 2024. Kotlin's rise reflects the industry's move towards more efficient, expressive programming languages, while Java's enduring presence underscores its reliability and extensive support network. The best choice ultimately aligns with your project's specific needs, team preferences, and future goals.

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