kotlinjava.kt

// Calling Java code from Kotlin
class KotlinClass {
    fun kotlinDoSomething() {
        val javaClass = JavaClass()
        javaClass.javaDoSomething()
        println(JavaClass().prop)
    }
}

==================================

// Calling Kotlin code from Java
public class JavaClass {
    public String getProp() { return "Hello"; }
    public void javaDoSomething() {
        new KotlinClass().kotlinDoSomething();
    }
}