Question

What happens when we say e.printStackTrace();? Here e is any Exception. Does it stop the normal execution and actually remove the activation records from the thread stack to give the stack trace of the exception? Is it a good idea to use it in applications?

Answer 1

Does it stop the normal execution

No.

and actually remove the activation records from the thread stack to give the stack trace of the exception?

No.

The information has already been captured. This happens in the constructors for Throwable ; i.e. when you new an exception, not when you throw it. The Throwable constructor calls the fillInStackTrace() native method which takes a snapshot of the stack and stores the resulting StackTraceElement[] in a private variable that is used later when printing the stack trace.

(For the record, this is specified in the javadoc for the constructors of Throwable.

Is it a good idea to use it in applications?

Well it is rather expensive and can produce a lot of output. But if you need the stack trace for diagnostic purposes … do it.