Kotlin VS Java

Language comparison: is it worth to move from Java to Kotlin?
18 August 2017   9249

Java is a language that has become one of the standards for business. Thanks to its multifunctionality, backward compatibility of versions and cross-platform software it is suitable for almost any task, such as the development of large portals and online stores, the creation of mobile applications, the work with corporate programs.

However, every coin has two sides. Thus, here 's a negative side to enterprise-oriented Java: the need to support all the existing projects at the time of the release of new versions seriously hinders the development of the language. You also have to wait for the appearance of plenty of important possibilities like first-order functions for years.

The JetBrains company was not happy with such state of affairs, so they introduced their own JVM-compatible language - Kotlin, -  back in 2011. Let's find out what are its disadvantages and advantages in comparison with his "parent".

Java vs Kotlin code Java vs Kotlin code


Moving from Java to another language is always a problem, often insoluble, especially when it comes to a large and old projec, as it is almost impossible to rewrite it entirely at a go. That's why Kotlin can be built into any existing Java code. This will allow the user to immediately continue to work on the project on Kotlin, step by step rewriting its old Java-parts.


The main task that JetBrains set for itself was to simplify the language and to finally solve some problems that  caused discomfort even to experienced Java programmers.
In Kotlin:

  • The declaration of the variables and the creation of objects are simplified.
  • There's no need to explicitly specify a type for the variables.
  • There's a support for string templates that allow you to use dynamic data and method calls right inside the line.
  • There's a set of tools that simplify and accelerate the writing of code for Android-applications. For example, you can access all the views with a unique ID in XML markup by adding just one line in the import section.

Additional Features

Kotlin uses several additional features that speed and simplify the process of writing code and give the developer a greater arsenal of the programming tools:

  • Lambda functions that reduce the amount of code that needs to be written several times.
  • Higher-order functions that allow taking functions as an argument and return the new functions.
  • Operator overloading that simplifies the call of the functions and allows using several variants of using operators with the same names in one scope.

Kotlin in general is focused on functional programming, thus, it is likely that there will be the support for other functions in the future. 

Speed of work 

The tests conducted usually show that the first assembly of the project on Kotlin is 10-20% slower than the similar on Java. However, this type of compilation is rarely used, while when carrying out more popular incremental assemblies, Kotlin as a whole shows no less speed than its "parent" and in some cases even slightly exceeds it. Therefore, it can be said that this language is not slower than Java.

Error protection

The emergence of the NullPointerException error disturbed even experienced Java developers and made it take a long time to figure out the reasons for the error and fix them. In Kotlin, the null and non-null types are additionally used, so it is impossible to write null and perform the operations leading to NPEs.

Expansion Capabilities

Kotlin is quite flexible and allows the programmer to add features missing specially to him without any special problems. To do this, the extension functions are used. Thus, you simply need to specify the prefix of the extensible type and apply the resulting function to any list. There's a possibility to add new features to both your own classes and the standard ones.

Documentation and the Community

On the Java's side there are several decades of active use and many implemented projects including quite complex enterprise applications. The low rate of the changes'occurrence also makes numerous solutions published in the community two or three years ago still relevant.

Kotlin can't boast of such an amount of available information, however, JetBrains documentation is quite well-developed, while the orientation to business structures increases both the number of programmers working with the language and its popularity in the thematic communities.

The Conclusion

In favour of Kotlin:

  • Rapid development and the emergence of new features that can not be implemented in Java.
  • Simplifying of the code writing.
  • Functional programming orientation.
  • Excellent extensibility.
  • Protection against NullPointerException.

In favour of Java:

  • A widely recognized standard in the development of enterprise applications.
  • A large fully formed community.
  • Slow development saves the developers from "race for technology".
  • Plenty of specialists mastered the language.

What technology do you choose, Kotlin or Java?

What programming language do you prefer? Kotlin or Java? Or maybe you are already using some of them? Please, share your thoughts with the community. Also, after the voting, you will be able to see what people like the most. Your opinion is very valuable for the Hype.Codes team.

52% (50 votes)
48% (47 votes)
Total votes: 97

Java SE 14 to be Available

Java SE 14 is as a regular support period version for which updates will be released before the next release
18 March 2020   351

After six months of development, Oracle released the Java SE 14 (Java Platform, Standard Edition 14), which uses the OpenJDK open source project as its reference implementation. Java SE 14 maintains backward compatibility with previous releases of the Java platform; all previously written Java projects will work without changes when launched under the new version. Ready-to-install Java SE 14 builds (JDK, JRE, and Server JRE) are prepared for Linux (x86_64), Windows, and macOS. The Java 14 reference implementation developed by the OpenJDK project is fully open under the GPLv2 license with GNU ClassPath exceptions that allow dynamic linking to commercial products.

Java SE 14 is categorized as a regular support period for which updates will be released before the next release. As a branch with a long service life (LTS), you should use Java SE 11, updates for which will be released until 2026. The previous Java 8 LTS branch will be supported until December 2020. The next LTS release is scheduled for September 2021. Recall that since the release of Java 10, the project has switched to a new development process, which implies a shorter cycle of generating new releases. New functionality is now being developed in one constantly updated master branch, in which ready-made changes are included and from which branches are released every six months to stabilize new releases.

These are some of the changes and updates:

  • Added experimental support for pattern matching in the instanceof operator, which allows you to immediately determine the local variable to access the checked value.
  • Experimental support has been added for the new “record” keyword, which provides a compact form for defining classes, avoiding the explicit definition of various low-level methods, such as equals (), hashCode () and toString (), in cases where data is stored only in fields, the behavior of work with which does not change.
  • This declaration will automatically add implementations of the equals (), hashCode (), and toString () methods in addition to the constructor and methods that control the change of data (getter).
  • Standardized and enabled by default is support for a new form of switch statements that does not require a break statement, allows you to combine duplicate labels, and allows use not only in the form of an operator, but also as an expression.
  • The experimental support for text blocks has been expanded - a new form of string literals that allows you to include multiline text data in the source code without using character escaping and preserving the original text formatting in the block
  • The informative value of diagnostics in case of NullPointerException exceptions has been expanded.
  • A preliminary version of the jpackage utility has been implemented, which allows you to create packages for self-contained Java applications.
  • A new memory allocation mechanism has been added to the G1 garbage collector, taking into account the specifics of working on large systems using the NUMA architecture.
  • Added API for tracking on-the-fly JFR events (JDK Flight Recorder), for example, for organizing continuous monitoring.
  • Added the jdk.nio.mapmode module, which offers new modes (READ_ONLY_SYNC, WRITE_ONLY_SYNC) for creating mapped byte buffers (MappedByteBuffer) that reference non-volatile memory (NVM).
  • A preliminary version of the Foreign-Memory Access API has been implemented, which allows Java applications to safely and efficiently access memory areas outside the Java heap by manipulating new abstractions of MemorySegment, MemoryAddress, and MemoryLayout.
  • Ports for Solaris OS and SPARC processors (Solaris / SPARC, Solaris / x64 and Linux / SPARC) declared obsolete with intent to delete.

Get more at the Oracle website.