Which is better/more efficient: check for bad values or catch Exceptions in Java

Question

Which is more efficient in Java: to check for bad values to prevent exceptions or let the exceptions happen and catch them?

Here are two blocks of sample code to ill

Answer 1

Well, exceptions are more expensive, yes but for me, its about weighting the cost of efficiency vs bad design. unless your use case demands it, always stick to the best design.

the question really is, when do you throw an exception? in exceptional situations.

if your arguments are not in the range that you're looking for, i'd suggest returning an error code or a boolean.

for instance, a method,

public int IsAuthenticated(String username, String password)
{

     if(!Validated(username,password)
     {
          // just an error
          // log it
          return -2;   
     }

     // contacting the Database here
     if cannot connect to db
     {
          // woww this is HUUGE
          throw new DBException('cannot connect'); // or something like that
     }

     // validate against db here
     if validated, return 0;

    // etc etc

}

thats my 2 cents