Can I use throws in constructor?

Question

I have to initialize file objects inside the constructor and for handling the exception, is it efficient using throws or should I go for try/

Answer 1

Consider a constructor, or for that matter any method, to have a contract. The contract for a constructor is very simple - you give me (zero, one or more) parameters and I'll give you back a constructed object. Good practice would suggest that this object should have its internal data structures properly initialised and invariants intact, although there's nothing in the language to enforce this per se.

If, for some reason the constructor cannot hold to this contract, then it should throw an exception. That might be because the parameters passed (if any) were not acceptable (pre-condition failure) or some external problems (file-system full, heap exhaustion, network outage etc.) prevented it.