Is invocation of exception.fillInStacktrace useful?

Question

I found an explicit invocation of e.fillInStacktrace() directly after creation of the exception Exception e = new Exception().

I think this is redundant, because the constructor of Throwable already invoke fillInStacktrace().

But maybe I overlooked something and this lines are useful:

Exception e = new Exception();
e.fillInStackTrace();
creationInfo = new CreationInfo(e.getStackTrace());

(public CreationInfo(StackTraceElement[] aStackTrace){...})

I think

1. the additional invocation of e.fillInStackTrace(); directly after creation an exception is redundant and will wast a lot of resource, because this method is expensive.

2. It seams that this construct is only needed to obtain the current stacktrace, therefore:

   creationInfo = Thread.currentThread().getStackTrace();
   

   is the better way.

Before filling an issue report I want to ask you if I have overlooked something?

Answer 1

You are correct on both counts: the biggest reason why fillInStackTrace is even available is to let you override it in your own exceptions where you'd like to save the costs of providing the stack trace information, or where you need to hide the information about the location from which the exception may have been thrown. See this answer for more details.