try, catch and finally

Definition

Code that might fail goes in try. catch handles a specific problem, and finally always runs afterwards, whether or not an exception happened. Catch the most specific exception first.

Example code

Parsing a number, with cleanup that always runs

class Demo {
    static int parse(String text) {
        try {
            return Integer.parseInt(text);
        } catch (NumberFormatException e) {
            System.out.println("Not a number: " + text);
            return -1;
        } finally {
            System.out.println("finished parsing " + text);   // runs in both cases
        }
    }

    public static void main(String[] args) {
        System.out.println(parse("42"));
        System.out.println(parse("abc"));
    }
}

// Output:
// finished parsing 42
// 42
// Not a number: abc
// finished parsing abc
// -1