Question

How much longer (in nanoseconds) does a try-catch take when catching an exception rather than doing a check (assuming message has HashMap type performance for lookup)?

    try {
        timestamp = message.getLongField( MessageField.TIMESTAMP );
    } catch (MissingDataException e) {
        //Not all messages contain this field
    }

vs

if (message.contains(MessageField.TIMESTAMP))
    timestamp = message.getLongField( MessageField.TIMESTAMP );

Answer 1

In short, the check is way faster. You should use the check because:

• Exceptions are EXPENSIVE! A stack trace must be created (if used, eg logged etc) and special flow control handled
• Exceptions should not be used for flow control – Exceptions are for the “exceptional”
• Exceptions are the code’s way of saying “I can’t handle this situation and I’m giving up… you deal with it!”, but here you can handle it… so handle it