Why Kotlin receives such an UndeclaredThrowableException rather than a ParseException?

Question

I have an extension method that converts string to Date in Kotlin.

fun String.convertToDate() : Date {
  var pattern: String = \"dd-mm-yyyy\"
  val         


        

Answer 1

It seems that your service is running in a different invocation context than your controller. As the service is throwing the exception you cannot catch it in the controller; it looks like you're calling the service directly, but due to code injection you really aren't. So what happens is that the invocation context (usually a thread) ends with an exception. This gets translated into a UndeclaredThrowableException with the original exception as cause.

There are two ways of dealing with this:

1. catch the exception locally in the service where the exception is generated;
2. catch the UndeclaredThrowableException in a separate try/catch and then re-throw the cause.

The first option should be preferred but requires you to handle the exception in the service. The second one looks too much like a hack to me, but it doesn't require setting up the exception handling in the service instead of the controller.