Exception

Throwing an exception

Throwable classes extend the Throwable class.

Exception and Error are the subtype of Throwable.

throw new NullPointerException

Catching an exception

val potentialFail = try {
  // your codes
} catch {
  case e: RuntimeException => println("Runtime Exception")
  case _: Throwable => println("Got some other kind of Throwable exception")
} finally {
  // The codes will be executed.
}

• finally is optional. It doesn't effect the return. It's used for side effects, such as logging.

Defining your own exception

class MyException extends Exception