How to mix kotlin code and java code
First
I must say, I misunderstood kotlin before. It’s a good language to simplify android development if you know java already.
Here is what the official says:
Kotlin is 100% interoperable with the Java programming language, so you can have as little or as much of Kotlin in your project as you want.
How to use java code in kotlin
You just have to create a java class besides your .kt file, then you are ready to go.
Just import that file by `import **` , then instantiate it as you would do with any class. Then it’s done.
Quite simple.
The source and the author
https://kotlinlang.org/docs/tutorials/mixing-java-kotlin-intellij.html