There's been a long debate going on between Kotlin and Java in the technological space. So today we're going to lay out everything you need to know about the two Android app development languages so that you can decide which language best suits your requirements.

Kotlin

Kotlin's History
JetBrains announced Project Kotlin in July 2011, which was a new language for the JVM that had been in development since 2010. Apart from Scala, according to JetBrains' Dmitry Jemerov, most languages lack the features that they should really possess. However, he highlighted Scala's lengthy compilation time as a drawback. One of Kotlin's main aims is to compile as fast as Java. JetBrains released the project under the Apache 2 licence in February 2012. The term "Kotlin" is derived from Kotlin Island, which is located near St. Petersburg.
In February 2016, Kotlin 1.0 was released.

Recently, even Google proclaimed that Kotlin is now its favoured programming language for Android app development. With the release of Android Studio 3.0 in October 2017, Kotlin has been available as an alternative to the standard Java compiler.

This programming language may be used for client-side web, server-side, and Android app development. Support for more platforms, such as embedded devices, macOS, and iOS, is on the way, thanks to Kotlin and Native. Individuals use Kotlin for client-side and server-side applications with JavaScript or JavaFX, to mention a few.

Understanding Kotlin

Kotlin is a Java-inspired, platform-independent, statically typed, open-source, and flexible language. For Android developers, Kotlin, alongside Java, is a fairly demanding language. It operates on a Java virtual machine (JVM) and is an excellent choice for developing Android applications, server-side applications, and other web-based applications. Kotlin blends object-oriented and functional programming in a very seamless manner.

The Key Features of Kotlin

Supports Java Interoperability
The strong interoperability of Kotlin with Java has enticed several Java and Android app developers to explore the language. It is supported by the JVM and is compatible with Java libraries and tools that allow full Java interoperability. Both languages coexist, which makes it effortless for developers to work productively.

With the help of the interoperability function, developers could quickly compile a single Android project in both languages. It also allows them to develop more Android apps in less time. So, if you need to access a Java function from a Kotlin class or vice versa, you can do it without any additional conditions.

Open-source
Kotlin is an open-source programming language. Besides being open-source, Kotlin also comes with a one-click tool that allows developers to translate existing Java code.

If you're an Android app developer new to Kotlin and want to learn it from the ground up, we recommend starting with some introductory courses. You can find plenty of them on the internet. These courses will definitely assist you in honing your skills.

Compact and Concise Codebase
As far as syntax and code clarity are concerned, Kotlin is miles ahead of Java. With Kotlin you can achieve a lot with merely a couple lines of code. You can work with less code, while improving the reliability of the code by decreasing issues and errors.

Furthermore, a compact and concise codebase provides a number of benefits, like readability, ease of maintenance, and the ease of implementing modifications as required.

Lesser Crashes during Runtime
This is perhaps Kotlin's most powerful feature, as it allows you to easily identify the NullPointerException while working on your project. This ensures that all variables are non-null and helps reduce the number of runtime crashes.

If you must keep a null value, add a question mark at the end of the variable type to limit the amount of crashes. This surely lessens runtime crashes.

Negligible Costs
This is one of the most prominent reasons why people prefer Kotlin as an Android app development language. There is low or no cost of adoption with the Kotlin programming language. You won't have to pay for a licence in Kotlin, as it's open source.

Lazy-loading
The lazy-loading feature basically boosts the startup pace, which is another eloquent advantage. By definition, it's an excellent solution for those who want to reduce the startup time of their Android apps so that their content is showcased faster.

The lazy-loading functionality can be used to load only the resources that are needed for the main memory. Kotlin is the best option, if you want to use this feature.

Null Safe Function
This is one of the most powerful features of Kotlin as it is a reliable language that you can use without any concern. Furthermore, the NullSafe function can help you prevent issues like "NullPointException."

You can also easily avoid using nullable types and have errors automatically corrected. This will assist you in simplifying your code for debugging and Android app development processes.

Java

Java's History
In the early 1990s, James Gosling created Java, an object-oriented programming language. It was created by Sun Microsystems. The project was started by the team to create a language for digital devices such as televisions, set-up boxes, and so on. Initially, C++ was proposed for use in the project, but it was rejected for a variety of reasons (for example, it needed more memory). Gosling tried to refine and fine-tune C++, but finally scrapped it in hopes of establishing Green, a new stage. Greentalk was the name given to James Gosling's project by his team, and the file extension was.gt, which eventually became known as "OAK."

Why the name "Oak"?
Gosling selected "Oak'' as a name after an oak tree outside his office. The oak is also a symbol of unity and has been recognised as a national tree by a number of countries, including the United States, Germany, France, Romania, and others. However, because it was already a trademark of Oak Technologies, they had to rename it "JAVA."
Gosling and his team held a brainstorming session and came up with numerous names, including Java, DNA, Silk, Ruby, and others.

Because of its uniqueness, the name Java was chosen after a long discussion. The term "Java'' is taken from an espresso bean known as Java. While drinking coffee near his office, Gosling came up with the name.
Java was developed based on ideologies such as robustness, platform independence, portability, multithreading, and high performance. It was also named one of TIME Magazine's Ten Best Products of 1995. Sun Microsystems, which owned Java, was later acquired by Oracle in 2009.

Java is presently being used across internet programming, mobile devices, games, and e-business solutions, among other things. Since JDK 1.0, there have been a few changes to the Java language, as well as several additions of classes and packages to the standard library. In addition to the language changes, the Java Class Library has undergone significant transmutations over the years.

Understanding Java

Java is object-oriented and a high-level programming language with minimal implementation dependencies. It's a general-purpose programming language developed to let programmers write once and run anywhere (WORA). This means that compiled Java code can run on any platform that is compatible with Java without requiring recompilation. Java applications are usually compiled to bytecode, which may run on any Java virtual machine (JVM), irrespective of the computer architecture. Java has a syntax that in many ways is identical to C and C++, despite the fact that it has fewer low-level features than any of the languages. Traditional compiled languages don't allow robust functionalities (such as runtime code modification and reflection) that the Java runtime allows.
Java 18 is the most recent version as of March 2022.

The Key Features of Java

Object-Oriented
Organising the program in terms of a collection of objects is a way of object-oriented programming, each of which represents an instance of the class.
The four main concepts of Object-Oriented programming are - Abstraction, Encapsulation, Inheritance, and Polymorphism.

Platform Independence
The compiler translates source code to bytecode, which is subsequently executed by the JVM. The bytecode can run across any platform, including Windows, macOS, and Linux. This simply means that we can create a program on Windows and run it on macOS, and vice versa.

Even though every operating system possesses its own JVM, the output produced by every operating system following bytecode execution is similar. This is the reason Java is referred to as a platform-independent language.

High Performance
The Java architecture is developed to decrease overhead during runtime, and at times, the compiler leverages a Just In Time (JIT) compiler, which compiles code on-demand and only compiles functions that are called, allowing applications to run faster.

Reliability
Java is a highly reliable programming language. It is constructed in a way that it emphasises on early error detection. As a result, the Java compiler can detect errors that are difficult to detect in other programming languages. Exception Handling, Garbage Collection, and Memory Allocation are the chief facets of Java, making it more robust than others.

Simplicity
Java is considered one of the simplest languages because it excludes complex features like operator overloading, pointers, many inheritances, and others.

Multithreading
Multithreading is supported by Java. This Java functionality enables the execution of multiple components of a programme simultaneously to maximise CPU utilisation.

Portability
Java code created on one system can be run on another system. Due to its platform independence, Java enables its platform-independent bytecode to be executed on any platform.

The Fundamental Differences Between Kotlin and Java

• Users in Kotlin can build their own extension functions, whereas Java does not allow this.
• Contextual conversions are unavailable in Kotlin, but they are available in Java.
• Null variables and objects are not available in Kotlin, but they are available in Java.
• Kotlin does not have static members for a class. Whereas Java has static members for a class.
• Objects are the primitive type variables in Kotlin, while objects aren't the primitive type variables in Java.
• Kotlin supports Lambda Expression, but Java does not. (Java 8 introduces lambda expressions.)
• The safety call operator is used to implement Null Safety in Kotlin. Java does not support null safety.
• Variable data type specifications are optional in Kotlin but necessary in Java.
• Kotlin is easier to deploy than Java as Kotlin can be executed within a few lines of code.
• Semicolons aren't needed in Kotlin programmes, but they are necessary in Java programmes.
• Because Kotlin has language scripting capabilities, you can use them actively in your Gradle build scripts, whereas Java does not have this ability.
• There are no wildcard types in Kotlin. But they are present when it comes to Java.
• In Kotlin, you can use the Lazy-Loading functionality. But in Java, this feature is not available.
• Kotlin is compatible with programming concepts like extensions, delegates, and higher-order functions. Java, on the other hand, is compatible with the OOPS programming concept.

If you want an in-depth, comprehensive comparison between Kotlin and Java, click here.

Which Language Should You Prefer?

Kotlin's advantages for Android developers are indisputable, and hence, Kotlin has the potential to become the programming language of the future. Many modern companies are embracing Kotlin as an Android programming language. Kotlin's future as the new Android programming language is unquestionably bright.

It's very possible that certain members of your team are already well-versed in Java. Because pivoting the entire team to Kotlin at once can be jarring, it's best to take it gradually, i.e., one person at a time. Due to its cutting-edge features, Kotlin will be widely embraced in the future. Hence, it's a good thing to start learning it as soon as you can.

On the contrary, Java is unlikely to be completely replaced, and it will continue to be a popular language for a long time. So take your time to become comfortable with the transition from Java to Kotlin.

Final Thoughts

So here's everything you need to know about Kotlin and Java, along with their key differentiating factors. Java is an older programming language and a more established language than Kotlin, while Kotlin has better features, for instance, concise code. Kotlin is a fast-emerging programming language that gives developers plenty of possibilities to experiment with current programming, making it an excellent language for developing Android apps. Because Kotlin is mostly identical to Java, we can fully adopt it because it accomplishes everything that standard programming should.

When we consider all the pitfalls of Java, specifically the issue with NullPointerExceptions, Kotlin seems to be the superlative language. Although the Android operating system is based on Java, it is still a crucial language for any android app development. If you wish to make sure that your Android app development solutions are more advanced than others, you should consider hiring Kotlin developers.

Ultimately, it's all about convenience. To be a truly proficient developer, you'll need to know the basics of Java as a programming language as well. However, if you are already familiar with it, it's recommended that you spend some time honing your skills in Kotlin.