Question

Consider these 2 pieces of code (you can assume execeptionObj is of type Object, but we know it’s an instance of Throwable):

1)

logger.log(Level.ERROR, (Throwable) exceptionObj,
    ((Throwable) exceptionObj).getMessage());

2)

Throwable t = new Throwable((Throwable)exceptionObj);
logger.log(Level.ERROR, t, t.getMessage());

During a code review for a project I’m working on, one reviewer is saying that the first way is not as efficient as the second way because it involves 2 casts. I just wondered what you thought. It seems like creating a new instance would involve some overhead as well.

Answer 1

The two pieces of code do different things. In the second, you are no longer passing exceptionObj, but “an unspecified Throwable caused by exceptionObj”. I don’t think that’s what you want.

Did you mean the first line of the second one to be:

Throwable t = (Throwable) exceptionObj;

It is very marginally more efficient, I’d guess, but would not let this decide the issue. Which is more readable is the key, and I think the (modified) second one is more readable.

Do you really have to case to Throwable? surely the logger takes a Throwable already?