Direct to point:

Java and kotlin both have different syntax but works quite same. Even if someone will look closely into the libraries of kotlin then one will know java code files are being used. Kotlin also use jdk for code compilation and almost all functions of jvm. But there are some points which makes kotlin better than java and reasons to opt for kotlin than java.

Like :

1. Coroutine : rather than using coventional thread way of java kotlin goves us the power to use coroutine that is much easier when it to comes to multi threaded applications.

2. Better syntax : kotlin come whith a very very lean syntax whoch internally cover more code but syntax very small.