Search:

What is that posted code supposed to show?
Why the if statement when the results looks like the code always does a return line?

Are you talking about another part of the program, not the throws clause?


How does it do that?

Can you explain what " stopped working" means?

What happens with the String returned by the inputCommandFile() method?

Did you read the tutorial? What you just asked does not make sense.
catch goes with the try statement.
methods use the throws clause

private static String inputCommandFile(String s) throws FileNotFoundException

That method is defined to throw an exception. Any code that calls that method must be ready to handle the exception...