Throws

This annotation indicates what exceptions should be declared by a function when compiled to a platform method in Kotlin/JVM and Kotlin/Native.

This annotation indicates what exceptions should be declared by a function when compiled to a JVM method.

Example:

@Throws(IOException::class)
fun readFile(name: String): String {...}

will be translated to

String readFile(String name) throws IOException {...}

This annotation indicates what exceptions should be declared by a function when compiled to a platform method.

When compiling to Objective-C/Swift framework, non-suspend functions having or inheriting this annotation are represented as NSError*-producing methods in Objective-C and as throws methods in Swift. Representations for suspend functions always have NSError*/Error parameter in completion handler

When Kotlin function called from Swift/Objective-C code throws an exception which is an instance of one of the exceptionClasses or their subclasses, it is propagated as NSError. Other Kotlin exceptions reaching Swift/Objective-C are considered unhandled and cause program termination.

Note: suspend functions without @Throws propagate only kotlin.coroutines.cancellation.CancellationException as NSError. Non-suspend functions without @Throws don't propagate Kotlin exceptions at all.