Creating a new instance of a KClass

In your case, Java reflection might be enough: you can use MyClass::class.java and create a new instance in the same way as you would with Java reflection (see @IngoKegel's answer).

But in case there's more than one constructor and you really need to get the primary one (not the default no-arg one), use the primaryConstructor extension function of a KClass<T>. It is a part of Kotlin reflection, which is not shipped within kotlin-stdlib.

To use it, you have to add kotlin-reflect as a dependency, e.g. a in Gradle project:

dependencies {
     compile "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"    
}

^{Assuming that there is ext.kotlin_version, otherwise replace $kotlin_version with the version you use.}

Then you will be able to use primaryConstructor, for example:

fun <T : Any> construct(kClass: KClass<T>): T? {
    val ctor = kClass.primaryConstructor
    return if (ctor != null && ctor.parameters.isEmpty())
        ctor.call() else
        null
}

You can use the Java class to create new instance:

MyClass::class.java.newInstance()