|  | Session 11 |  | 
Throw exception
Before we are going to proceed with the exception handling, let's have a look at how it is possible to break the program flow with own usr friendly message when an exception occurs:
static int factor(int n) {
  if (n < 0)
    throw new IllegalArgumentException("N cannot be negative!"); // an exception is thrown
  int result = 1;
  for (int i = n; i > 1; i--)
    result = result * i;
  return result;
}
If n equals to -1, the program flow is interrupted and the following message is printed out:
Exception in thread "main" java.lang.IllegalArgumentException: N cannot be negative!
    at Example.factor(Example.java:7)
    at Example.main(Example.java:3)
|  | Session 11 |  |