when to use exceptions

[dojob]

I have read through about exceptions and it is mentioned that exception handling usually requires more time and resources and it is advisable that do not use exceptions whenever it is possible to deal with simple, expected situations.

So, does that means that division by zero should not be handle by Arithmetic Exception since it can be done in following way.
If so, then when should ArithmetricException be used?

int number1;
int number2;

if (number2 == 0)
  System.out.println("Divisor cannot be zero")
else
  System.out.println(number1/number2);

Similarly, null pointer can be done in following way. Am I wrong?

if(pointera!= null)
  System.out.println(pointera.toString());
else
 System.out.println("pointera is null");

[DarrylBurke]

You didn't bother to reply to two useful responses on your earlier thread. Why should we expect any better behavior this time round?

db

[dojob]

You didn't bother to reply to two useful responses on your earlier thread. Why should we expect any better behavior this time round?

db

I am sorry for my own rudeless behaviour for not replying on my own thread and i should have realise this earlier. Thanks for informing so that I won't be making the same mistake next time.

[kjkrum]

Don't worry about micro-optimizations. If a method can't comply with its contract, it's almost always better to throw an exception than to count on the programmer checking the return value.

[dojob]

Don't worry about micro-optimizations. If a method can't comply with its contract, it's almost always better to throw an exception than to count on the programmer checking the return value.

does it mean that the micro-optimization is insignificant and it is better to do in in less trivial way and focus in clean and simple code?

[gimbal2]

does it mean that the micro-optimization is insignificant

Yes!

and focus in clean and simple code?

Yes!

Generally, clean and simple code is actually more trivial, or as it is also known: the code is more "dumb".

The Developer Insight Series, Part 1: Write Dumb Code -- Advice From Four Leading Java Developers

[kjkrum]

More important even than the fact that the Java compiler does a better job optimizing simple code, is the fact that simple code is easier to understand and maintain. Following the Principle of Least Surprise is almost always more important than shaving a few milliseconds off the execution time.