Performance Evaluation of Kotlin and Java on Android Runtime

Abstract: This study evaluates the performance of Kotlin and Java on Android Runtime using four benchmarks from the Computer Language Benchmarks Game suite, for which a total of 12 benchmark implementations are studied. The metrics used to evaluate the performance includes runtime, memory consumption, garbage collection, boxing of primitives as well as bytecode n-grams. To benchmark the languages, a benchmark application has been developed intended to run on an Android phone. The results indicate that Kotlin is slower than Java for all studied benchmarks by a varying factor. Furthermore, the use of idiomatic Kotlin features and constructs results in additional heap pressure and the need of boxed primitives. Other interesting results indicate the existence of an underlying garbage collection overhead when reclaiming Kotlin objects compared to Java. Furthermore, Kotlin produces larger and more varied bytecode than Java for a majority of the benchmarks.