kotlin_reified_functions.kt

inline fun <reified T : Activity> Context.open() = startActivity(Intent(this, T::class.java))
inline fun <reified T : Activity> Context.openForResult(code: Int) = startActivityForResult(Intent(this, T::class.java), code)
inline fun <reified T : Fragment> newInstance(): T = T::class.java.newInstance()

Usage: 

open<LoginActivity>()

openForResult<LoginActivity>(INTENT_CODE)

supportFragmentManager
    .beginTransaction()
    .replace(R.id.login_fragment_container, newInstance<LoginFragment>())
    .commit()