JAVA - return statement within the for loop

Question

I have a simple question about the "return" statement. Example is in the code. I always think the isPrime(n) is always "true". Because the "return true;" is at the end of the method, it should over-write previous returns. Any one can help? The codes are running perfect, producing the right results.

private boolean isPrime(int n) {
    for(int i = 2; i < n; i++) {
        if (n % i == 0) return false;   
    }
    return true;
}

Answer 1

'return' exits the function returning whatever value you return. The last return is never reached so it won't return the default value.

Answer 2

No, a second return does not override an earlier one, it is never even reached. Control leaves the method immediately upon return .

(The only way for that not to happen would be to have a second return inside of a finally block. That would indeed change the return value. But is is highly discouraged)

Answer 3

No, once you return from a method, you're done. If you want to convince yourself, insert print statements, or run it through a debugger.

Answer 4

Functions don't fully execute and then return, they can exit at any point during the execution with a return statement.

So if a number is found to n % i == 0 then the subroutine will return false and exit.

If the function completed the for loop and never resolved the if statement it returns true and exits.

Answer 5

If if (n % i == 0) is true it executes return false; and will exit the method. return true; will only be reached if return false; can't be executed.