11.2 Kotlin and Java
Originally introduced by Sun Microsystems in 1995 Java is still by far the most popular programming language in use today. Until the introduction of Kotlin, it is quite likely that every Android app available on the market was written in Java. Since acquiring the Android operating system, Google has invested heavily in tuning and optimizing compilation and runtime environments for running Java-based code on Android devices.
Rather than try to re-invent the wheel, Kotlin is design to both integrate with and work alongside Java. When Kotlin code is compiled it generates the same bytecode as that generated by the Java compiler enabling projects to be built using a combination of Java and Kotlin code. This compatibility also allows existing Java frameworks and libraries to be used seamlessly from within Kotlin code and also for Kotlin code to be called from within Java.
Kotlin’s creators also acknowledged that while there were ways to improve on existing...