Important: This news article covers an old version of Javalin (v0.2.0). The current version is v6.1.3.
See the documentation page for up-to-date information.

Most of Javalin was re-written to Kotlin in version 0.2.0. The SAM interfaces were left as Java, as well as the main Javalin-class which has method-declarations with SAM parameters. This had to be done due to limitations in Kotlin itself (,
The rest of the library will be ported to Kotlin if this issue is resolved, or and alternative solution is discovered.