News

JetBrains Releases Kotlin 1.0 Beta for JVM and Android

• By John K. Waters
• November 3, 2015

Software development toolmaker JetBrains has announced the availability of the beta release candidate of Kotlin 1.0, its open source programming language, for both Java Virtual Machines (JVM) and Android. All major language changes are completed, the company says, and the binary format is finalized. This beta release is part of the process of "wrapping up preparations for the official release."

Kotlin is a statically typed language similar to Scala, Gosu, Ceylon and Fantom. It compiles to both JVM byte code and JavaScript. JetBrains, maker of the code-centric Java IDE, IntelliJ IDEA, began developing the language in 2010, and the company uses Kotlin in production of that IDE and other products. The company says it has more than 250,000 lines of Kotlin code in production as of this release (not to mention the code in Kotlin itself). JetBrains has claimed that the language is more stable at run time than Java, because it can statically check weak points and supports things like variable type interface, closures, extension functions and mix-ins.

"We reached the level of interoperability where freely putting Kotlin alongside Java is transparent for Java clients," said project lead Andrey Breslav in a company blog post. "Java can be called from Kotlin and vice versa, sources can be mixed in one project, resulting .class files are totally compatible with Java tooling."

Kotlin is actively used in production at JetBrains and by other companies and individual developers "from Web-service back-ends to Android apps," Breslav said. A list of some Kotlin users, including a short note explaining how they're using it, is available on GitHub.

After the release of Kotlin 1.0, all updates to the language and libraries will be backwards-compatible, Breslav said -- which means that a newer compiler will work with older binaries, though older compilers may not understand newer binaries, and older binaries will keep working with newer binaries at run time, though newer code may require newer dependencies. All updates apply to the JVM/Android support only, Breslav emphasized. "The JavaScript support remains experimental for now and will have its own release later on," he said.

Prague-based JetBrains released Kotlin in July 2011 for distribution under the Apache 2 Open Source License. "We know that Java is going to stand long, but we believe that the community can benefit from a new statically typed JVM-targeted language free of the legacy trouble and having the features so desperately wanted by the developers," Breslav told ADTmag at the time. The company released the first Kotlin milestone (M1) in April 2012 with a plugin for IntelliJ IDEA. Milestone release 8 was released in July 2014 with amped up reflective capabilities, enhanced inlining functions, new error reporting for platform signature clashes, and an expanded standard library with new functions. In April 2015, the company announced a Kotlin Eclipse plugin. There are also plugins currently available for Android Studio, Maven, Gradle and Ant.

More details are available on the company blog page, and the language docs page.