Kotlin vs Java: Feature, Performance, and Use Case Comparison

For more than 20 years, Java has dominated software development, serving as the foundation for innumerable web servers, Android apps, and enterprise programs. Still, a major change in the programming landscape was brought about by the 2011 release of Kotlin and Google’s 2017 decision to make it an official language for Android development. In this article we present a thorough comparison between Kotlin vs Java with an emphasis on features, performance, and real-world applications.

What is Java?

The well-known object-oriented, high-level programming language Java was first created by Sun Microsystems and made available in 1995. Oracle currently owns Java, which is used by over 3 billion devices. Numerous operating systems, including Windows, Mac OS, and the different UNIX versions, support Java. Java is now used to create a wide range of software applications, such as games, online apps, desktop apps, and mobile apps, among many others.

Write Once, Run Anywhere (WORA) is the goal of Java, a general-purpose programming language. This implies that compiled Java code doesn’t require recompiling in order to operate on any platform that supports Java.

What are the Features of Java?

Java is a language with many features. Java is constantly changing with each new version, which is released every six months. Some of the primary characteristics of the Java language are as follows:

1. Object-Oriented:

Everything in Java is an object, and the language is entirely object-oriented. Java is compatible with OOPS concepts, including classes, inheritance, encapsulation, and polymorphism. Because Java is based on an object model, it is also extensible.

2. Independent Platform:

Java programming doesn’t depend on any one platform. Java code is turned into platform-neutral byte code rather than machine-specific code. The JVM runs the code on the underlying platform and executes this byte code. Java is a Write Once Run Anywhere language because of its feature.

3. Simple to Understand:

If developers are familiar with C or C++, they can readily pick up Java since it inherits features from those languages. Java is incredibly simple to learn from beginning, even for someone who is not familiar with computer languages.

4. Secure:

Java’s architecture ensures security. It is not necessary for a developer to work directly with the operating system or underlying memory. Because Java offers automatic garbage collection, developers aren’t concerned about memory leaks, management, or other issues.

5. Architecturally Neutral:

Any type of CPU can run Java byte code. On many processor types, JRE manages code execution automatically.

6. Portable:

Without requiring any modifications to the code, Java code created on a Windows computer can run on a MacOS computer and vice versa. No changes to the operating system’s code are required.

7. Robust:

Java is a very robust language that has stringent type checking, robust compile-time error checks, and runtime exception handling.

8. Multithreading:

Multiprocessing and multithreading are incorporated into Java. Java has features including race conditions, deadlock handling, thread managing, and monitors.

9. High Performance:

Despite being interpreted, Java maintains its high performance. Performance is enhanced with the JIT (Just In Time) compiler.

10. Distributed:

Because the internet is a distributed environment, Java is the most widely used programming language for creating internet-based applications. It is made for distributed systems.

What is Java Performance?

The speed and effectiveness of a Java application or system are referred to as Java performance, and they are commonly measured by how long a job takes to finish or how many resources are used. In many applications, performance is crucial, especially those that call for low latency, high throughput, or real-time processing.

The code itself, the JVM implementation, and the hardware it runs on are some of the variables that might impact Java performance. Inefficient algorithms, high memory utilization, excessive CPU usage, and I/O activities are examples of common performance bottlenecks. Often, profiling, tuning, and optimization can be used to find and fix these problems.

What is the use of Java?

In this section focus will be on Java’s applications. For instance, Java is a strong and flexible programming language that has been used to make some of the best software in the world, including enterprise apps, games, and web browsers. There are countless uses for this programming language, but we don’t have enough time or space to discuss them all. Java may be utilized in almost any business and while creating any kind of program.

These are just a handful of the many uses for Java-based software development.

1. Enterprise Java Applications:

To satisfy their business goals, companies and large enterprises design their own workflows using the widely used Java EE framework.
Java is a computer language that businesses prefer because it is stable, strong, safe, and dependable. Because Java is a programming language used in many banking systems, discussing Java security is fairly simple.
Businesses that use Java include:

• Google.
• Spotify.
• Uber.
• HCL.
• Pinterest.

2. Web-Based Programs:

Java’s scalability and resilience make it a popular choice for web application development. Popular Java-based web applications include Pinterest, Tumblr, and LinkedIn. Additionally, Java is a great option for creating intricate web applications because to its ease of interface with other technologies.

For example, Java is used to create Hadoop, an open-source framework for handling massive data collections. Another well-liked Java framework, Spring, is frequently used to create microservices, which are tiny, independent modules that combine to create a bigger application.

3. Games:

Perhaps we all saw the Java splash screen when we launched our favorite games on our ancient phones back in the 2000s. Many of us have played Gravity Defied, Gangstar 2, or Doodle Jump for hours on end. Furthermore, we continue to play well-known Android games that were also made with Java.

4. Apps for Science:

Java was a popular programming language for creating accurate scientific applications because it enabled large-scale calculations and simulations of scientific research.

Another example of a Java application is Orca. It was developed for scientists that use ocean simulations in their studies. The advantage of using Java to create this application was that it allowed for the usage of a single code base that any computer could process.

5. Mobile Apps:

The greatest programming environment for creating and testing mobile applications is Java Micro Edition. You can develop applications that work on a range of devices, such as smartphones, tablets, and embedded systems, thanks to portability and platform independence. Thus, the most widely used mobile applications that utilize Java programming are:

• Netflix.
• Tinder.
• The QR Reader.
• Google Earth.
• Uber.

Java is still primarily used in Android app development, where it is possible to create a variety of native apps and their back-ends.

Check out more details in our blog What Is Java Used For? Key Features and Role in Programming.

What is Kotlin?

In 2011, JetBrains, the company behind the Intellij IDEA, the most intelligent Java IDE, unveiled Kotlin, a programming language. Kotlin is, has been, and will continue to be free. The source code is accessible on GitHub, and it was created under the Apache 2.0 license.

This general-purpose programming language, which runs on the JVM, has a robust statically typed syntax. Google declared Kotlin to be an official language for Android development in 2017. Kotlin is an open-source programming language that creates a distinctive platform by fusing functional characteristics and object-oriented programming. The information is broken up into many parts that cover related subjects with straightforward and practical examples.

Kotlin is a contemporary programming language that brings joy to developers. Because Kotlin is simple to learn, you can start developing robust applications right away.

What are the Features of Kotlin?

JetBrains created Kotlin, an open-source, general-purpose, cross-platform programming language. It is completely compatible with Java. Kotlin is the favored language for Android development and is ranked as the fourth most popular language among developers, according to Stack Overflow.

At Google I/O 2017, Google announced that Kotlin would be supported on Android in addition to the current languages, Java and C++. On May 7, 2019, Google also declared Kotlin to be its preferred language for Android development.

1. Functions within:

Lambda expressions and higher-order functions are stored as objects in Kotlin. Runtime memory cost may therefore arise from allocating memory to the function objects, classes, and virtual calls.
In the end, using the inline keywords asks the compiler to copy the function’s inlined code at the calling location rather than allocating memory.
Consequently, the runtime memory cost caused by the lambda functions and function references is decreased by inlining the higher-order functions and their lambda argument body to the call-site.

2. Overloading of operators:

Unlike Java, Kotlin enables you to give user-defined types custom implementations of the specified set of operators.
In Kotlin, you can overload relational, binary, and unary operators. There are specified symbolic representations for each of these operations. Either the extension function or the member functions can be used to overload operators. These functions are preceded by the operator modifier. Additionally, Kotlin has standard functions for every kind of operator.

3. Language Specific to a Domain:

Domain-specific languages, or DSLs, are a type of “mini-language” that is used to explain how a particular application component is constructed. In order to make the code reusable and understandable, it is utilized to extract the relevant portion.
For instance, DSL will use Kotlin and create something reusable and intelligible on top of it if you wish to reuse the Kotlin code for a specific purpose.

4. Delegated Assets:

Giving someone the authority or power to perform several tasks is known as delegation. Likewise, Kotlin uses Delegation attributes to provide language support for delegation.
With the help of this functionality, you can develop and implement attributes just once and then utilize them repeatedly to assign other application code tasks.
The design pattern known as delegation occurs when one object or property assigns a task to another helping object rather than carrying it out themselves.

5. Classes of data:

The purpose of the classes is to store data. The data in these classes can frequently be used to derive certain standard functions. These classes are known as data classes in Kotlin. In addition to removing errors, Kotlin’s ability to separate data classes from common classes lowers the number of lines of code and provides Android developers with a vast amount of self-generated code.

6. The coroutines:

Kotlin coroutines made it simple for developers to program both synchronously and asynchronously.
Kotlinx.JetBrains created the coroutine library for Kotlin coroutines.
Lightweight and almost free, coroutines are threads. To handle the demanding requirements of lengthy calculations that use excessive amounts of memory, it is costly to create numerous threads.

7. Null Safety:

Accessing a member of null references in any programming language, including Java, is the most frequent bug that can result in runtime NullPointer Exceptions and occasionally system crashes or application failure.
Kotlin’s type system is intended to remove the potentially dangerous null references—also referred to as the “billion dollar mistake”—from the code.
There are two kinds of references according to the Kotlin type system: those that can hold null references and those that cannot.

8. Smart castings:

Java and other programming languages need variables to be explicitly type converted before their properties may be accessed. Nonetheless, Kotlin has a feature called smart casting that keeps track of conditions inside the if statement.
The Kotlin compiler will only grant access to a variable if it finds one that is not null and has a type equal to nullable.

9. Singletons:

One of the simplest software design patterns, singleton ensures thread safety by ensuring a class has only one instance. For instance, it is far less expensive to share a single database connection across several objects rather than establishing unique database connections for each object.
In a similar vein, we can develop a single configuration manager within the application rather than several to address various difficulties. The singleton class is quite easy to define in Kotlin.

What is Kotlin performance?

A thorough understanding of the principles is necessary before starting any optimization assignment. Understanding what makes code performant is the first step when it comes to Kotlin, a language known for its succinct syntax and compatibility with Java. When it comes to Kotlin apps, performance encompasses a number of factors, from how fast the code runs to how efficiently it utilizes resources like memory and processing power.

Kotlin has a special set of features that affect how well it works. These capabilities can speed up your apps, but if you don’t use them properly, they could cause bottlenecks. The null-safety feature of Kotlin, for example, avoids null pointer exceptions, which is good for dependability but might introduce needless tests that slow down speed if used carelessly.

What is the use of Kotlin?

Kotlin is incredibly flexible. Approximately 2 million experts in programming used Kotlin at least once in 2021 alone. Moreover, approximately one million of them speak Kotlin as one of their three main languages.
Today’s programming experts use Kotlin in the following ways:

1. Development of Back-End Websites:

Because Kotlin/JVM requires less code than Java, even when the code is same, many programmers utilize it for back-end web development. The majority of Java-related vocabulary can be reduced with Kotlin. For example, compared to Java code, Kotlin code is typically shorter and more straightforward.
Kotlin is very useful for large teams and projects. Efficiency levels can soar when many modules share this common code for back-end development.

2. Server-Side Development:

Kotlin is excellent for server-side web development with Kotlin/JS in addition to the back-end.
Kotlin/JS not only gives you access to robust web and browser APIs, but it also ensures that you stay type-safe at all times.

3. Full-Stack Web Development:

Front-end code can be written in the same language as back-end code by full-stack web developers using Kotlin.
In order for them to function in the browser, Kotlin compiles them both into JavaScript. It makes it possible for shared libraries, programming paradigms, and syntax to remain constant between the front end and back end.

4. Android Development:

Kotlin is the best programming language for Android development, with more than 190 countries and 2.5 billion active Android users. It is a modern statically typed programming language used by over 60% of professional Android developers
Android Studio, the official Android development integrated development environment (IDE), supports Kotlin. Thus, when working on Android development, programmers can utilize Kotlin’s code with ease.

5. Mobile Cross-Platform Development:

Kotlin’s Multiplatform Mobile (KMM) lets you utilize the features that are native to both iOS and Android devices, which sets it apart from other cross-platform app development tools.
KMM’s greatest feature is that it eliminates the need to add new programming languages to a code base in order to create cross-platform applications. This not only makes mobile development easier, but it also makes it possible for users of iOS and Android to have the experience they want.

6. Data Science:

To extract knowledge and insight, data scientists employ scientific procedures, systems, algorithms, and approaches. In their line of business, they frequently use Java to accomplish this.
Since they can write their code in Kotlin and yet utilize all of the usual Java libraries from earlier projects, Kotlin is the ideal substitute.

Use cases of Kotlin vs Java:

This is a representation that compares the use cases of Kotlin and Java:

Make sure to explore our detailed guide on the 10 Must-Know Web Development Languages for Success in 2025 Whether you’re a beginner or a seasoned developer, these languages are key to shaping the future of web development.”

Popularity: Kotlin vs. Java:

Both Kotlin and Java are still quite popular among developers as of 2023, particularly for creating corporate and Android apps. Although specific usage figures may change among studies and reports, in general:

• Java’s popularity keeps growing since it is one of the most popular programming languages in the world and ranks highly on indices like GitHub’s Octoverse and the TIOBE Index. More than 95% of the more than 1.8 million websites in the world employ JavaScript, a popular programming language for front-end and back-end development. Java is still widely used in business settings and in educational institutions, even with the rise of more recent languages like Kotlin.
• Kotlin’s popularity has been rising rapidly, particularly among Android developers. Kotlin’s development on Android has been greatly impacted by Google’s advocacy for it. Millions of developers are currently using Kotlin, according to JetBrains, which recorded a significant year-over-year rise in Kotlin usage.

FAQs:

Conclusion:

Because of its broad library support and platform neutrality, Java has been a mainstay in software development for decades, powering web servers, enterprise applications, and Android apps. However, because of its current features, null safety, and short syntax, Kotlin has rapidly become popular, particularly for Android programming. This comparison shows that Kotlin is frequently chosen for new Android projects and teams that prioritize productivity and readability, whereas Java is still best suited for legacy systems and businesses. Both languages offer unique benefits in the current programming environment.

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