Previous, Gradle supported only the Groovy language, but Kotlin adds a statically compiled language that be used for scripting and for making domain-specific languages.
"The notion behind this is really just to make build programming into a first-class engineering discipline and move it away from its historical legacy," said Miko Matsumura, chief marketing officer at Gradle. "In the past, typically, this has been done with XML configuration or even with shell scripting. It's moved up in the world of programming."
Kotlin claims advantages like speed, engineering quality, and IDE support because of its Java lineage, said Hans Dockter, Gradle CEO and the founder of the technology. Developers can use Kotlin to build Gradle plug-ins, and as Dockter notes, "The Android community is deeply embracing it."
Like Groovy, Kotlin runs on the Java Virtual Machine. Gradle is not worried about developers needing to ramp up on programming with Kotlin, which officially debuted in a 1.0 release in February, because "it's very easy to learn if you know Java," Dockter said. There are no plans to add support for other languages to Gradle besides Kotlin as this time.
Gradle 1.0 was released in 2012. "The main attraction to Gradle is that you can create builds that are fast, that have very good dependency management, and it allows you to have a very high degree of automation," said Dockter. It also integrates with a lot of existing technologies.