orElseThrow

If a value is present, returns the value, otherwise throws NoSuchElementException.

the non-null value described by this Optional

if no value is present

fun <X : Throwable> orElseThrow(exceptionSupplier: () -> X): T

If a value is present, returns the value, otherwise throws an exception produced by the exception supplying function.

A method reference to an exception constructor (with no arguments) can be used, for example: ::IllegalStateException.

the value, if present.

exceptionSupplier

the supplying function that produces an exception to be thrown.

if no value is present.