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Java

Posted by SZE SZE XU
SZE SZE XU
9,759 Points

predict output practice problem

Note : Execution commandline : $ java exception_handling one

class exception_handling {

    public static void main(String args[]) {

        try {

            int a = args.length;

            int b = 10 / a;

            System.out.print(a);

            try {

                if (a == 1)

                    a = a / a - a;

                if (a == 2) {

                    int c = {1};

                    c[8] = 9;

                }
            }

            catch (ArrayIndexOutOfBoundException e) {

                System.out.println("TypeA");
            }

            catch (ArithmeticException e) {

                System.out.println("TypeB");

            }
        }
    }
}

a) TypeA b) TypeB c) 0TypeA d) 0TypeB

Answer: c Explanation: Execution command line is “$ java exception_handling one” hence there is only single string that is in args array, making its length 1, hence “a = a/ a – a” in second try block is executing which throws arithmeticexception which is caught by catch of firts try block as the nested try block does not have a catch block which can detect ArithmeticException. Hence 0TypeA is printed Output: $ javac exception_handling.java $ java exception_handling 0TypeA

I dont get this, if it is passing one to the program, a would be 1, System.out.print(a) will print 1, why it is 0 ?

1 Answer

Seth Kroger
Seth Kroger
56,416 Points
Seth Kroger
Seth Kroger
56,416 Points

You're all wrong. :-P True output (I renamed the class to Test1):

treehouse:~/workspace$ javac Test1.java                                                                      
Test1.java:5: error: 'try' without 'catch', 'finally' or resource declarations                               
            try {                                                                                            
            ^                                                                                                
1 error                                                                                                      
treehouse:~/workspace$
Seth Kroger
Seth Kroger
56,416 Points

Seriously, even if you fix the compiler errors the output would be E) 1. There's no ArithmeticException to throw because a = a / a - a evaluates as a = (a/a) - a or a = 1-a